Of course, recurring payments work completely differently. A shockingly large fraction of recurring payments are from people who never got around to cancelling it. They're already getting what they want, any email just risks disturbing this situation.

I still get yearly email summary of my donations. They don't need to send more, and they could not send it if their objective is to stay under the radar

That could be true. I guess I could try giving a one-time donation from another account and see what happens.