Back in my younger days (when I was also a tornado chaser) I was employed as an auditor for the IRS for a few years. This was in the very early 1980s, and I’ve slept quite a bit since then, but here are some particular memories of “profiling” (which was very common…it was called “flagging”) that could result in a possible audit:

#1: charitable contributions, and not necessarily in excess of 10% of income (although the latter would definitely have triggered a closer look before audit).
#2: disaster loss. Don’t know if this is an actual allowable deduction these days, but a significant disaster loss was always flagged for review.
#3: any and all financial holdings in the Cayman Islands; this was because back in the day, the Caymans were a very popular place for drug money laundering.
#4: (this one is my favorite because I actually audited more than one person who did this) claiming your household pets (usually your dogs) as dependents. One person I audited claimed upwards to 14 Dobermans (the number might be off by one or two) and was incensed…INCENSED I tell you, that we DARED to audit his return.

So, call it profiling, call it flagging based on general past/current possibility of abuse of a particular category, it has always been thus and shall always be…