No I think you did the right thing. You're trying to be consistent right? You can't do some things some times and some things other times if you're trying to be consistent. Don't worry about the checkout girl what does she know anyway? She know's nothing about what you're trying to do with Zander etc so she has no right to say anything, she shouldn't have said "Oh that's ok everyone else doe it" either. Does that mean if everyone else steals that you should too??? Pffft to her I say.

ETA: I wait and give stuff to Jonah after it's paid for too.