I was a very gullible child and this is still one of my major personality traits. When I was a child, my mother was (and remains) a master of constructing appropriately vague statements which mislead the gullible, usually into doing the proper thing. The UNICEF scam is an example.
We were given these little cardboard boxes that you'd fold into a tiny carrying case for the money. There was a slot for coins at the top. We were supposed to go out the day before Halloween and collect money for UNICEF. I was a curious child, and always wanted to know how things worked. So I asked how the money is taken out of the box. "We can't open the box," my mother said. She was, naturally, worried that after I collected the money from neighbors, that I would open it up and take a portion for myself. But I just wanted to know how the system worked. Based on what she said, I asked if the box had some way of sealing itself. "The only people who can open it are the UNICEF people," she said. "You mean, it won't come open once we put it together?" I asked, in my gullibility.
"We can't open the box," she said, knowing full well that her vague language would make me think it was impossible to open the box, while all she meant was that we mustn't open it.
She was a good person, well-intentioned, but she'd read a lot of child psychology books and had methods for guiding children: Never issue a prohibitive command, always seek to redirect, deflect or fatigue the child's wrongful impulses.
So I went out and cheerfully collected the UNICEF money. No one was mean to me. But at some point, maybe that day, or at some time after, I developed an attitude about the UNICEF thing. I felt used. I perceived that they were using my special status as a child to gather money. I didn't like it.
Years later, as a grown-up, I decided that it is wrong to enlist gullible kids to collect money for your cause. UNICEF is a good thing. Community service is a good thing. Involving kids in helping others is a good thing. But making kids feel used is not. Maybe it works great for you and your kids, but I hate the idea.
It came around to my son this year, and I didn't do anything to interfere. He was all set to go, but in the excitement of Halloween, neither my lovely wife nor I remembered the little cardboard box. This year, I gave a dollar to the one kid who offered me the UNICEF box. The expression on the kid's face was: Can you believe this sucker is giving me money that I'm just going to steal? I almost feel sorry for the guy.
The end of my only experience as a UNICEF dupe was that a boy at school told me he had stolen more than five dollars from the box. I told him that I knew very well that those boxes cannot be opened once they're built.