Yeah, basically as soon as you push, then there's no guarantee that someone else hasn't checked it out. That's how I see it anyway.

It'd be nice if git let you push (for backup/protection) without letting other people see it or check it out yet.

It's a fairly common practice to prefix branches only intended for your own work with your initials and a slash, e.g. jd/my-work-in-progress. You can't guarantee that nobody else will work off it, but it's their own fault if they do.

We treat branches for tickets (prefixed with the ticket ID) as owned by the owner of the ticket: feel free to check out, but if the owner changes it underneath you, tough.