No such beast exists. Not for a centrally located system anyways. To do what you are specifying, you'd need doorway mounted sensors running a positive-negative polarity, and the sticker would have to be designed in such a way as to take that charge and create a signature signal that would be detected. Area broadcast won't work because of signal strength loss with range, there's no guarantee the signal would remain perfect anywhere near the door. Nothing is impeccable, can't count the amount of times the cashier in Home Depot has scanned the magnet tag only for the stupid alarm to then go off as I walk out the door. I did a job in a ladies boutique on time and the alarm went off as my boss walked out. Turned out 15minutes later he was innocent of any shoplifting when the security guard finally found an old magnet strip buried in the bottom of an unused pocket of his tool case. So your special sticker would need to be totally different than any other manufacturers, would need to be physically placed by your employees in such a fashion as to not be easily removable, would have to be strong enough to bypass clothing or other obstacles like purses or bags yet weak enough not to trip the alarm when shoppers walk past the sensor while browsing.
Impeccable isn't feasible.