Is push frequency becoming an issue?

I do wonder when Google says enough and limits how many can be sent per minute, hour, day, etc. I'm honestly surprised they haven't done this already (or maybe they have with all the recent GSB bans that most are blaming the push networks for), especially when some networks are sending out 3 at the same time and hundreds per day to each user.

I subbed to someone by accident the other day I decided to see what kind of ads were being run so didn't unsub. Immediately after subbing I started to receive non stop "spam". When I tapped clear notifications