You can push whatever you want over email. I have used email as a federated queueing system... It worked fine.

I'd be very curious what gave you this idea. The ActivityPub vocabulary contains a number of social network related activities that can operate over a decently large vocabulary of object types, events being only one of them.

You're confusing "an event Im going to" with "an event signaled by a program"

Thank you for clarifying that. I would hope that I can be forgiven for not understanding what you meant seeing how stingy you are with your words. Even so, I can't say I've heard anyone that works on ActivityPub projects call "Activities" events.