- Mailing address on account was bogus per Google Maps
- 1st credit card charge attempt failed, 2nd one passed. Name on credit card did not match name on account (although both CCs passed Stripe's zip code and CVV checks)
- Taxpayer claimed to live and work in California, yet W-2 didn't have any CA state tax info (boxes 15-20) populated
- Every value on the W-2 was a whole number (no pennies)
There's more, but I don't want to give away our entire algorithm, which could help thieves navigate our system and others