I had this happen on a consumer startup with referrals. Every month like clockwork one person would fake referrals to get a free moth, which involved jumping through non trivial hoops (re-installing all, creating content in the fake account, going back). all to save $5, and when we had a free plan with almost the exact same quality.
I think the thrill of beating a system and getting away with is as much a factor as anything. And I get it.