Probably this could go on heroes sounds as well.. but the issue is mostly with items.
The thing is that you can hear enemies using certain items in the fog.
There was this game where we were uncertain aftear a big team fight if the enemy was doing roshan. As I panned my camera over the rosh pit I was able to hear the enemy Void's MoM sound activation...
Is this intended? it can certainly turn a game around in the rights conditions (in that same game I was playing spectre and managed to steal the aegis with a bb)