On Sunday, 17 March 2019 15:30:52 UTC+2, John DeRosa OHM Ω http://aviation.derosaweb.net wrote:
A couple of comments;

- You are able to attach documents to messages.
- True that a bot could try to join the group but I mandate that they tell me why they want to join the group which should allow me to not allow bot to join. But if someone/something gets past this step and posts some crud, I can (unlike RAS) retroactively eliminate the post and remove the user account.
- Someone from outside the US should absolutely be allowed to join including the ISS! I will try to determine why this might be and correct it, then report back.

- John OHM Ω

I joined (outside USA) without any problems.