I know someone would have to be insane for this but I'm thinking like the maniac in question. if someone were to giftbomb someone then later tell staff after a falling out "I didn't gift them that, they bought it from me," how could staff ever verify that? It would get even more muddy if there was any $ transactions between the two for art or something, or irl reasons to send $.

My ex once gifted me a dragon on the same day I paid him rent, could he present that crossroads and venmo screenshot to staff and get me banned?

I don't envy staff at all. It seems like a mess to sort stuff like this out.