Ditto. Helping some non-profits, we were really hurt by people typo-ing a $10,000 donation when they meant to only donate $100. We quickly learned from that mistake.

We also learned about how credit card thieves test credit cards. We saw hundreds of donation attempts. Stripe had us refund those that went threw, which costed us money in fees. Fortunately we were able to put some quick measures in place to stop them temporarily & then better measures for long term success.