Comment by Brybry

I'm well aware that some spam also use unsubscribe links as a signal to spam more. I use my gut to decide if I mark as spam and/or block or try the unsubscribe link if it exists.

My gut says unsolicited marketing emails, from popular sites I've never used before, like Brooks Brothers or Robinhood (especially after a "Welcome to ${site}!") or US public school event notification emails are all probably legit mistakes.

I could see even a public school system having issues with getting flagged as spam if they don't include an easy method to unsubscribe because then marking as spam+blocking becomes the best option in response to wrong address.