The idea of mines are so that enemy tanks don't spot them. Mines and explosives aren't always spotted friend. Don't give me BF3/CoD bullshit, I know the ARMA engine well enough to know that tanks should not avoid and see mines as objects (atleast not always). When planting a mine in ARMA2 tanks would actually drive over them, same goes for ARMA1 and the OF series. Its kind of what the purpose of mines are..