Someone just randomly joined my Tailnet

Relevant answer on reddit:

> Hi there,

> I’m sorry you experienced this. It must have been quite unnerving and isn’t a great experience.

> This happened because poczta.pl wasn’t known as a shared / free email provider to us before you brought it to our attention.

> By default, Tailscale tries to account for domains on shared email providers (like gmail.com) where users will share a domain, but are unrelated and should not share a single tailnet.

> Since we were unaware of poczta.pl, it was treated as a company domain, which meant others with the domain ended up on your tailnet as they joined. You’ve been split into your own tailnet now and the domain has been marked as shared. Thank you so much for calling this out, and sorry again for the confusion.

You should definitely have to prove ownership of your domain to have it be treated as a company domain. This being the default makes no sense.