I do checks using the Safe Kids form (anyone have a scanned copy? I'm rather tech poor in that department, not to mention I can't find it) and am almost always at a check up event.
Because of this, I want to see the child in the seat in the vehicle when you arrive. . .document how seat is installed, location of seat, type of seat used.
THEN I will take it out, record the model #/serial #, check for recalls.
If your seat is okay (no recalls, still appropriate for your child) I will install it (I learned the old fashioned way - I do it, then I will teach you. Which makes sense to me because I'm discovering/problem solving any installation issues along the way). Once I'm confident of a good install, I will take it out and have you to install it.
Along the way, I talk about: when a seat is outgrown, what the next seat will do (rear face then turn - look for high weight limits on both), when/how to adjust the harness, how to use LATCH & seat belts ('cause you may use different vehicles).
At a check up event, we have instructors/senior checkers review the install and do some quizzing of the parents (asking parent to state what I told them).
There is also liberal flirting with/drooling over the little people, congrats for "soon to be parents" (Several of the instructors have OB nursing background and most techs are parents and/or work with young children) and praise / encouragement / thanks to parents coming in (our check events are by appointment).