It's not uncommon to see donations of 5k USD and up in a single transaction. And oftentimes all this person gets in return - that is, if the camgirl.. apologies, streamer notices the sum come in at all - is a "you're so sweet thanks!".
I just can't understand what they're hoping to get out of handing away so much money. Do they believe theirs will be reacted to differently? But why them? It's just so irrational!