In 2v2, the case is more that in mid-game, they just get spammed everywhere. A good reason you shouldn't leave one area completely uncontested for long, but if it has you can guarantee there will be tons of mines.
Sounds like a good gameplay mechanic then: it forces players to be aggressive and rewards players who manage to hold a part of the map for a long period of time. The near-removal of the freebee call-in comeback mechanic has greatly improved the game, lets not turn that around by making comebacks a lot easier.