@sam Not sure if you want opinions here, but given your stated concerns, I think meeting groups where they are is probably a good idea. If you're still concerned about the opsec drawbacks of their chosen venues (and you should be) then I'd recommend involving yourself in their opsec decisions when you get there. Help them draft policy on what uses of a VC-funded tech are safe and reasonable. Help them set up alternatives if possible.
But never login to Twitter again. That's the master's tools now.