A big key is being dressed for the part, if you look like a well enough trust fund kid then all you need to do is act somewhat stoned out of your ass and be like "oh shit man I forgor my bad..." if you ever get caught.

This is in inverse with walmarts and wallgreens/cvs having fucking bulletproof protective glass and the like all over with armed security ready to plug you in the back at a moments notice (because handling poor clientele versus richer clientele are drasticly different).