If trademarks are misused they can be turned generic, like aspirin or thermos. So, companies that own them make sure they are used only as adjectives: a Kleenex facial tissue, not a Kleenex. But, in everyday life, people use Kleenexes, Xerox copies, and so forth. Do writers ever get in trouble for misusing a trademark as a noun or verb in fiction? I've heard companies will go after media that don't follow these standards. It seems unnatural to have a kid ask another kid if they want to play Legos plastic toy bricks instead of just Legos.