Oh I just remembered another thing I once did to my eldest son.
When he was about 7, we were in Big W, and he was being really naughty, taking off and hiding from me so I couldn't find him etc... he really just made my time there terrible.
Anyway, on the way out he was bugging me for the sweets that are near the registers, so while he was being annoying, I whispered to the lady on the check out to have a word to him, and told her what he had been doing. So, after a few seconds, the lady turns to James and says "Excuse me little boy... I have been watching you on the cameras in the store and this is your last chance. If you come in here and be naughty for your mum or anyone else again, I'm sorry to say you won't be allowed back in."
Ever since that day, I have not had one bit of trouble with my kids going into any shop. It was kinda funny though because the lady remembered him and James would behave so well whenever he saw her.