Are such things really a concern in a game where few battles rarely last longer than a couple minutes? After all, this thread is asking about tactical roles, not strategic, so campaigns aren't a worry here.
I've had campaign battles, even raids, last days. Sure, a battle may be a series of skirmishes as in BT set battles but only amateurs plan for ten turns of fighting followed by guaranteed R&R -as OPFOR, I would never allow the players any rest, if I could avoid it. The worst campaign players were those who expected to only fight for a couple of minutes at a time, they'd run out of ammo and took risks just to end a scenario without concern how that scenario carried on to the next battle, which could easily begin 30 seconds later.
Operation Market Garden (1944) had airborne units tasked with taking and holding a series of bridges until 30th Armored Corps relieved them in 3 days. The battle ended 9 days later with most of the British airborne troops, out of supplies and munitions, surrendering in Arnhem. The delay wasn't part of Monty's plan. A large number of tactical events eventually tie into strategic results and most tactical plans fail to survive the onset of battle.
As a Clan player, I have knowingly sent Elementals on one-way missions, where I didn't expect them to return -That's what they were for.
As a GM, I had no qualms about dropping players into impossible situations, especially when they didn't bother to ask the right questions.