While true in theory, I don't it plays out this way in practice, mainly because the asymmetry in the security example is so vast (fake sticker = $1 one time payment, real sticker from paying for the service = $100 month) which means that the likely outcome is that fake >> real; which means that, empirically, the sticker will have virtually no signaling value in practice, and not dissuade thieves at all. It wouldn't even be good advertising, since getting the security service would provide no deterrence, and your brand would in short order become synonymous for 'waste of money'.

The handbag case is quite different, mainly because thieves are not testing the validity of your handbag at great consequence to your health and safety. The signaling value of selective enforcement that you describe seems about right, though.