Excellent! Though despite his adherence to rules, he would have appreciated who were the actual troublemakers and who had just been at the wrong place/time. As for the children, etc, Alicia would have definitely seen the different side of Percy coming out with Lucy. I can see them having interesting discussions about Muggle school vs home-school (which is what Percy is doing) - so all in all it sounds fun!
No worries, Percy knows just how long and far he can indulge his daughter (plus it gives him an excuse to get a treat for himself), and he's very good at putting his foot down. But either way, it can mean intersting interactions at the shop!