See now THIS should have come with a warning!
It could be that people don't sanitize their kids' sippy cups and just buy new ones as soon as the old ones start getting....say....three weeks old? How am I supposed to know that boiling these will deshape them?
Oh, now that I think about it, these cups being insulated should have given me a warning, right?
Aw, man, maybe today's consumer IS dumb enough to require warnings like "may get stuck in your teeth."