I agree with those above that she is teaching the kids to use bad behavior to get a reward.
I don't think it is about the sweets at all, it is about simple behavioral training. She is teaching them that if they misbehave long enough, she will give in, whether it is with junk food or letting them do whatever they want. To break the pattern, she will have to chose to refuse to give in. It is hard to hold your ground to change behavior in kids and the frequency of the misbehavior will increase for a while until they finally realize that they can't win.

I think using food as a reward or punishment is setting a kid up for problems later in life. She needs to find a more neutral object or an activity or desirable behavior as a reward. Something along the lines of, they behave and they get to go to the park to play (exercise). Another simple example is that I used getting to wash their hands with their favorite soap as a reward when potty-training.

As for the sweets and crisps, I grew up in a family that believed having a house cram-packed full of all kinds of food, especially junk food, was a sign of prosperity. You couldn't go visit my relatives without constantly being asked if you were hungry. (My house was the only one in the family to only have 1 fridge and no extra pantries.) As kids, my generation had free access to eat whatever we wanted, yet more often that not, the junk food would spoil before it ever got eaten. These days, I have all kinds of junk food in my house and my kids would rather have yougurt or string cheese or cereal for a snack. Like my aunts and uncles before me, I throw away more stale junk food than we eat. The junk food in our house isn't contingent on behavior.
( flirting with badgers What? It sounded good at the time., Mon 13 Oct 2008, 23:26, Reply)