sadly at least here in ontario around toronto, a lot of the time if you signal before changing lanes the people tend to purposefully block you and not let you infront of them, training many to not want to properly signal. very childish mentalities here.
If they used PLA(made of cornstarch) which is common for fdm 3d printing then theres no threat of microplastics from what ive read. it is biodegradable, but very slowly.