I think you have set them up to "steal" the candy. I agree with a PP--they are sneaking the candy--not stealing. I think YOU are sending a bad message to your kids by calling this stealing.
My sister did not let her kids have candy. Her oldest could not care less about any type of candy. The other 3 like it.
On Halloween, she would dress them up and take them trick or treating. They would be so excited because they loved candy so much (more than normal, lol). They'd get home, have to turn it all in and she'd keep the "good candy" and they'd have to get rid of the sticky type. I remember one year my nephew took the candy and put it in his
lego containers in his room. He's go in there and sneak some candy and one by one, his sisters would join him and then the youngest tattled to mom about what they were doing.
Years later, I saw a teacher who had a niece of mine in school (5th or 6th gr) and I told him that my niece went to his school. He asked her name, I told him and he says, "Oh I know her!! She comes into my room and always eats all the candy on my desk!"
Ugh...yes, that's because mom and dad do not allow candy (or better said, very limited). I remember them making Christmas cookies and instead of letting them have a cookie after they came out of the oven, they just had to look at them and wait til days later. I always thought that was cruel.
All that taught them to sneak it and all but the oldest did.
I do not think that you should fill kids up with candy and sugar but I also do not think you should "teach" them they have to sneak to eat some candy. It is the forbidden fruit and you have taught them that.
Unless they have a problem like a PP's kid does, I truly think you are going overboard and making it worse than it ever would be otherwise.