Why would they want to spend effort trying to brute-force addresses to show me emails that they already have the ability to sent to me and I didn't generate them any revenue from?
I used similar (well, plus addressing with localpart=name+<service>) a long time ago and once got emails to name+paypal@example.com even though that was a suffix I'd never used. Some enterprising person out there had obviously obtained one or more of my service-specific addresses and was trying to game my attention by changing the identifier to something 'important'. That's when I personally ditched the approach.