I would think payment systems would flag cases where payments to a vendor rise in a possibly dangerous way indicating possible embezzlement.
There might be checks made after thresholds of $1,000, $5,000, $25,000, $100,000, $500,000, $2 million, etc. are crossed, to be done by a different person each time.
There’s typically 30 days to pay, enough time to do checks.
When DH worked for a DOD contractor, he caught a co-worker doing something very similar and turned him in to the FBI. He had to testify in Federal Court.
The guy went to prison, but I can’t recall for how long. That was in the mid-’90s.