I think making little signs that warn you about a minefield are going to help people.
don't try to flank and no minefield problem
why dumb down a great game just do not go very close to the edge simple as that.
I think minefield volumes are best used as minefields: marked or not, but able to kill both teams, and not as protection. If you want to prevent players straying from the battlefield, I think a blocking volume is best.