One question for you CAP if I may: In an emergency braking (without ABS & no change of direction needed), is it better to lock up the wheels on a wet surface rather than having the tires kept at the point of maximal efficiency or "threshold braking"?
As to the seatbelt issue, last time I brought passengers with me, one of them didn't put on his seatbeat on. I had to argue with him to put it on because he didn't want to (said something about being stuck and possible need to get out in a hurry). Couldn't believe my ears about what he said. Also placing the seatbelt around your hip as low as possible might save you from internal abdominal injuries in the event of a head on crash.
never deliberately lock your brakes. once you've done that, you've lost the ability to control the car. you'll go farther before you stop.
the key is to keep them just short of lockup, and you'll stop pretty quickly. i think it was rt that mentioned about possibly taking a performance driving course. this is an excellent idea, as it'll safely allow you to find your limits, as well as your cars, and learn to maximize them. i didn't have the benefit of such a course, but rather i learned by experimenting(playing) in big empty parking lots. these days, i don't recommend that.
i don't move my car, unless everyone in it is belted in. if they don't want to put it on, then they can hoof it.