McD's is having this weird Monopoly sponsored promo where you collect stamps and trade them in for prizes... Was there anything similar in the US recently? If yes, is this promo bullshit or actually worth it?

I mean, my first try already yielded two of the three stamps needed for a car, and I just can't believe this contest would be this easy if there wasn't a catch, like printing millions of two of the stamps needed for a prize and only 5 or 10 of the last one, that way everybody and their Brother would find the first two (literally, my brother also has the same two car stamps), get real excited about winning a car, only to never find the third one. That's it isn't it? That's the catch, two of the three seals are moot because you'll never find the third one, they're only there to make you excited for "owning" 2/3 of something.