The candy bowl

I have a candy bowl on my desk with Lifesavers mints in it. They're delicious candies, so I keep it stocked. I appreciate it when people enjoy the candy, and I encourage them to help themselves while they are in the presentation center. BUT, it bugs the hell out of me when they load up their pockets on the way out the door. Am I being unreasonable, or is that just plain rude? Once, these two girls came in and asked to use the phone, and while the one girl was on the phone, they both proceeded to load handfulls of candy into their pockets. I just about died of shock! I stood there completely astonished at their behaviour, just looking at them like "are you actually serious?" Apparently they were because they kept loading up and then left. At the risk of sounding like a rant...what has happened to manners in today's society?! I could go on and on about the rude stuff people do in here on a daily basis, but I'll save that for another day.
The formal days of "yes sir" and "thank you ma'am" when our parents were kids are gone, but does that mean we have to throw common decency out the window as well?