I would have no problem with these folks, as long as they don’t accept prizes. EXCEPT, they take up space. There is a limit to participation for a reason. If you’ve ever watched one of these races, it is a sea of runners packed curb to curb. It is not fair if these unpaid bandits get in the way of serious contenders who have paid their fees.
Really, only a handful of people expect to win a prize (except the I make it medal).