Do any of the riding programs like Strava have a function that can tell if your a A,B,C rider? I'm in some meetups and it would be nice to be able to warn people ahead of time to check what their level is to make sure they aren't going on a ride thats to hard.

That would be an interesting algorithm to implement. I'd love it if Strava would do that.

Then again, just because someone's HR/Power metrics show that they're capable of being an x rider, doesn't necessarily mean that they'd find the most enjoyment/benefit out of riding at that level.

Should send these suggestions to the big cycling app developers.

this would be really hard to automate. I think there would have to be people that rated themselves first

A, B, C level mean different things to different clubs. You'd have to create a standard in the process.

Yep!

Right. And a lot of clubs just say what that means: this is a 20 mph ride, this is a no drop ride where people wait at the tops of hills for stragglers, etc.