[Taqwus]

You use a scout to attack and retreat the expensive heavy cavalry, because it's not exactly a brilliant move to waste ten expensive heavy cavalry unsupported at mages with troops -- given that they may smack into orb lightning, astral fires, magma eruption, nether darts, F9W9 lava warriors, et al. If they're a mix of summon-spammers and attackers, you could lose 'em all for no gain.