Definitely the new restraint laws. Maybe some info on how to fit each type of restraint and what is correct and incorrect? You could have some photos on correct and incorrect?
Also, and this may sound dumb but some parents just don't know, how to do up a car seat properly. I've seen some really SHOCKING and dangeous ways of doing up a car seat, twisted straps, too tight, too loose, parents have added padding underneath/around their child etc.
Great idea, but a real legal minefield. We had a VIc Roads guy come to do a talk on the new car seat laws and he basically said that he and anyone at Vic roads cannot fit your seat, or even advise if it has been done correctly. He basically advised that we needed to see a proper fitting station for any help.