Someone just randomly joined my Tailnet

I think I became an owner of an organisation I don't own the domain of.

When I log in via Google with [[email protected]](mailto:[email protected]), the name of the tailnet is [email protected]. Only people I invite can join the network and everything works as expected.

However, I logged in via Google with [[email protected]](mailto:[email protected]) and the name of my Tailnet is poczta.pl .

Other people who created a free poczta.pl email account and created a free Google account with it can simply log in to Tailscale via Google to access my Tailnet. I wasn't aware of this.

This April a guy from Warsaw joined my Tailnet and connected his AC IoT unit and Home Assistant nodes to my Tailnet. I kicked him out in panic, now I feel bad for breaking his setup