Houdini in a carseat
I don't. I've been blessed I guess. My kids are fairly happy in the car. My youngest didn't like long trips in his infant seat...and my oldest once screamed for 45 minutes straight while I drove from the northeast side of Pittsburgh to the northwest side (I had driven from Allentown then stopped for dinner with an aunt, and my daughter was quite happy to escape her carseat. But then when I put her back into it to complete the drive to my grandparents' house she was NOT happy! I stopped a couple of times to try to calm her, but she just started screaming again as soon as I put her back in the seat, so I just clenched my jaw and pressed on.) But other than that, they've been pretty compliant about the whole carseat thing. Yeah...sometimes they *try* to get out (particularly Jason), but so far Jessica--who is 6--is the only one capable of getting herself--and her siblings--out of seats. And she knows it is in her best interest to wait until the vehicle is parked so that she remains safe.
But I have run into a fair share of parents who have troubles with "Houdini children." Some parents seem to feel that this only needs to be dealt with as a rebellion issue--the child needs to learn to comply with the parental directive of staying in the carseat. My opinion is that if your child is escaping from his carseat there is a bigger problem than rebellion. A 2-3 year old really should not be capable of escaping from a child safety seat.
As a Certified Child Passenger Safety Technician, when I hear about kids escaping from carseats and I start asking questions about it, I usually end up coming to one of two basic reasons for the escape: The wrong seat is being used for the child, or the harness is not tight enough. Neither one of these bode well for a crash situation.
In the case of the "wrong seat," the wrong seat can either be a shield style convertible (tray shield sitting in front of the child or a T-shield), or it can be a case of a child moved into a belt positioning booster too soon.
With the shield style seats, the design of the seat prevents the harness from being very snug around the child. There also isn't hip restraint, which can allow a true Houdini child to wiggle out of even a fairly snug harness. Some kids just don't like the bulky shield in front of them (perhaps makes them feel claustrophobic?), so they will do whatever they can to get out. Shield style seats generally aren't favored in the safety community because the child is expected to impact on the shield as part of the restraint--this is like you or I hitting the dashboard. It may keep you from going any further forward, but it hurts and can cause significant injury (including in rare cases death--but broken bones and internal organ injury are more common). 5-point style harnesses are preferred because they reduce the impact risk, they also incorporate hip straps that help to hold a child down.
As far as belt positioning boosters, children generally aren't mature enough to use these seats safely until they are 4-5 years old. Even if they can be coerced into sitting still, if they are under 40 lbs they are better protected in a harnessed seat. Especially if you are using a shield style booster like a Gerry Double Guard or Cosco Grand Explorer you should know that a significant risk of these seats is having the child "fold" over the sheild and suffer serious abdominal/spinal injuries, and secondly ejection is a very real risk in side impact and roll-over crashes. These seats aren't FAA approved because they fail the roll over test required for FAA approval. (This is also my chance to mention that old seats DO expire! I just last week confiscated a Gerry Double Guard from the Care Net Crisis Pregnancy Center donation bin at my church. It was made in 1997--8 years old. Now I think I've got the folks at my local Care Net pretty well trained to toss stuff like that...but no point taking chances! Anything over 5 years old that comes into a carseat check we are REALLY looking for an excuse to replace it with a new seat, 10 years old will get it replaced for age in and of itself. The issues with old seats are that newer technology provides better protection, and older seats are often missing parts/instructions that are vital for proper use.)
Harness tightness was the second major category I listed for reasons for children being able to get out of car seats. The button to release the harness generally requires more force to release it than a typical 2-3 year old can generate. Even my almost 5 year old daughter can not let herself out of her seat. The harness should be "snug as a hug." There should not be slack in the harness, but it shouldn't be cutting into the child. Puffy winter coats should not be worn with carseats, as they result in loosening of the harness straps. In the winter time, when you get out to the car (which is hopefully pre-heated), take off the kids' coats, buckle them into their seats, and then put the coats on them backwards, and cover up with blankets as needed (we keep a small fleece blanket for each child in the van). For a child using a belt positioning booster you might be able to get away with just unzipping the coat, buckling the seat belt, then zipping the coat back up over the seat belt.
Now yes, there are "Houdinis" out there. When it comes to those kids, I recommend a proactive training approach. First, try to be REALLY alert for a day or so to any time the child runs head-long into a wall, or piece of furniture, or whatever. Make a big deal about how much it hurt--make that event memorable in the child's mind. Then schedule a "training drive." Make sure to bring along one of your child's prized stuffed animals, and put it on the seat next to your child--unrestrained--don't let the child hold it. Drive in a quiet neighborhood without much traffic/danger. Suddenly slam on the brakes. The doll will go flying. Grab up the doll and make a big deal about looking for injuries--perhaps find one and bandage it up quickly with some cloth strips you have conveniently tucked in your pocket. Then turn to your child with very animated emotions, and say "OH MY GOODNESS! It is SO good that you are buckled in your car seat. If you hadn't been buckled you would have flown right along with your teddy bear. And then you would have gotten hurt very badly! Remember when you ran into the chair this morning, how much you got hurt? This would have hurt a LOT more!!!"
Kids are very visual, it works. Then when you buckle the child in in the future you remind the child "remember how your teddy bear flew? You don't want to do that, do you? You will get owies. Okay, so keep your seat belt on, just like Momma keeps her seat belt on." BTW, if you and your partner don't both wear seat belts, there is no better time to start--kids pick up on that. When I was 3 I questioned my father--"why do I have to be in this seat if you don't wear your seatbelt?" Well he started wearing a seat belt! 1976.