I've definitely noticed that if use Uber infrequently, I consistently get marketing promotions for "40% off" of your rides.

This might be specific to my market, but it happens really consistently.

Honestly, I just think about it like a marketing analyst. Who would you try to entice back onto your platform? High value users, who show interest (i.e. opening the app but not taking rides). It really becomes easy to game most marketing promos this way, but Uber's is particularly gullible.