What about also implementing a "afk timer" as well? You are inactive in the SB (or any manned gun for that matter) for 2 1/2 minutes, you auto tower? So if someone pops in with intent to prevent use, they'd have to at least push the mouse or tap a key even min or so? Ran into this a couple of times myself, where there was an enemy CV right in front of the SB, but no one could get into it and it wasn't firing a shot.
A +1 for the 1 hour waiting and for the Name Tag.
Bino
The System Message for the SB being crewed, would be a coding nightmare I think.