In the US you can hide that opt-in in unreadable terms, can’t you? In the EU that will be harder though as there the opt-in has to be easily readable and obvious to the regular user, as well as feature an option to decline without making things non-functional that do not need that for their very functioning. In any case, people will be surprised how inshittified AI will be able to become once they have done the same they have done to regular search.