I've been asking for this for a while now (since GalCiv 2 release), asking for a command that will make ships do nothing. I've been calling it a fortify command (much like the command in the civilization games), but I've asking for so long that I'm willing to let it be called just about anything else. The problem is, I don't like the sentry or guard commands. I like keeping ships idle. I don't like how those commands will wake ships up and demand orders. I don't like how they demand my attention.
In GalCiv 2, I could get the results of do nothing by ignore them. This didn't mix well with sentry or guard commands. A ship that I choose to ignore looked the same as any ship that just woke up from guard or sentry. There were tools that allowed you cycle through idle ships back then. Because of the difficulties, I opted to reject the sentry and guard commands as I found my strategies to be more effective. It suited me.
Unfortunately, GalCiv 3 has rejected idle ships, thereby rejecting my strategies. I can't leave my ships alone some place while reinforcements arrive. I can't leave sensor ships sitting there watching things. I can't assemble fleets while an enemy is nearby. Etc, etc.
Don't you dare talk about pass turn as though it is a valid solution. To use it, you have to press it for every ship and fleet, every turn. Its too much mouse clicking. I really really don't like it.
This is me asking for the devs to implement a command that does this. Make a command that makes ships do nothing until I tell them to do otherwise.