Print and laminate mine registration cards that both team HQ's will have X amount before game starts. Make big info board in both bases and in off game zone that will state new rule changes, so people can see them also on the game site. State that all mines need to be registered before use. Use big staple guns to attach the registration card to the mine (assuming its made from wood). State that using non registered mines is forbidden and in case you find mines without registration card visible, they can be cleared instantaneously and in combat situations those can be run over without being destroyed.
Then try to get the message down from commanders and platoon leaders to get all players who have mines in one place before game starts so they can figure it out who get and how many registered mines in use. Because I believe the idea would be that not all cars for example would be stacked with mines.