CG have consistently stated that they will not implement any changes that prevent players from playing the game how they want to play it. That’s why they won’t ever allow officers to remove teams from TW defences, for instance. (Though allowing players to remove edit their own TW defence squads would be a welcome addition that wouldn’t compromise their stance).
TB is the ultimate guild communication challenge. If you’ve got players ignoring the map instructions (I’m assuming you are also using the text commands on the map to explain that zones are closed?) then either the communication needs to improve or the player needs to move on to a guild that matches their free-spirited play style.
I’m a TB officer in my guild and was very proud when we got our first ever 43* haul in RotE last time around. I post platoon assignments and phase briefings every single day during TB on Discord but still very occasionally get members who stray from them, especially if what the briefing says doesn’t align with what the map instructions say.
TL;DR: don’t wait for CG to implement this. They won’t. Improve your guild’s communication and/or remove those that can’t follow instructions. This is the way.