I've always had to manually enable this feature. I've never experienced it on by default across multiple platforms and deployments.

Do they ship this by default? I thought it had to be enabled: https://tailscale.com/docs/features/tailscale-ssh#configure-...

How do you mean? You have to run a command to enable tailscale ssh, it isn't on by default.

Tailscale SSH is not enabled by default.