You're likely going through a Tailscale relay when you're out of your house too. It's still an extra hop through their servers, but yes it "just works".
According to them, not necessarily [0]. They do have relay servers (they call them DERPs) [1] but they're only used in rare situations where UDP is blocked entirely.
I admit I wasn't able to understand most of those explanations so I could be wrong. :)
I admit I wasn't able to understand most of those explanations so I could be wrong. :)
[0] https://tailscale.com/blog/how-nat-traversal-works/
[1] https://tailscale.com/blog/how-tailscale-works/#encrypted-re... under "Encrypted TCP relays (DERP)"