Don't squads text and phone each other these days to coordinate showing up? Every time a wish of this nature comes around, some of the reason are in vein of players wanting to be able to not have to log into the game to find out something is not to their liking. The current terrain, a player or squad they don't like, how the fronts look, and the arena numbers.
I've always suspected a feature like this has not been offered so you will log in to check these things which more often than not, you will up one or two sortie before logging out. Bodies taking part in action in the MA tends to attract more bodies to take part in the action.