Ah, I meant that units which the user has explicitly asked to fortify which are in cities would get the permanent-F state (to indicate that they're not getting a bonus from the user's action), not that all units inside cities without other orders automatically get an 'F' icon (to indicate the automatic defense bonus).

(It's good to know that it's not just me that uses "fortify" to mean "go to sleep until I wake you". Perhaps we need such an order for non-CanFortify units?)

From bug #20501:

"Currently there's nothing stopping players from needlessly fortifying their units in cities in the mistaken belief that this will help. Perhaps if units in cities never reach "fortified" state (grey fort icon) and are permanently "fortifying" (yellow "F") when inside cities, and if a city is built around them they go from fortified to fortifying, would hint (somewhat obliquely) that something funny is going on?

"I don't want to take the order away entirely, as I sometimes use it as an alternative to Sentry when I don't want a unit to wake up and hassle me every time a foreigner passes by."