Medicaid and medicare make up 50% of the "abuse" (primarily overpayment), which again points towards companies milking the system, not individuals https://washingtonstand.com/article/gao-finds-15-major-feder...
So I dug a little deeper: roughly 94% of Medicare/Medicaid dollars and 89% of SNAP dollars passed audit reviews in 2025, but I can't find any national percentages for beneficiary fraud rates overall (which is sort of what we are talking about).
Provider fraud does appear to be the main driver of healthcare losses if we look at the enforcement evidence, but that does not mean every improper payment is abuse. It does seem the programs are audited quite extensively (unlike what some other comments in this thread are claiming).