I've never tried boiling water in a paper cup, but just might, after hearing about this new book:
Fifty Dangerous Things You Should Let Your Children Do
I think most of us parents balance the danger-safety-(trust?) factor throughout our kids' days. Tonight, I watched the thrill my 1-year-old got from figuring out how to use a step stool to create "stairs" up to a children's table in our kitchen while I cooked. Up and down he went, saying "tr! tr!" (stair! stair!). And of course, he had a micro-tumble during one up-down session. Risk factor? 3 out of 10.
That said, he's probably not ready to man the grill yet. Or boil water in a paper cup.