In some early tournaments, the casters would have to avoid looking at Roshan fights, because the other team would inevitably hear (or feel!) the bass-heavy sound effects from Roshan's attacks and movement.
Later versions of the client added an option to mute those sound effects, for precisely this reason.
It especially screwed over pre-siren Roshans (which don't seem to be much of a thing anymore). But yeah, there's still a lot the sounds can give away, like a Roshan play, a sneaky smoke, enemy tormentor attempts, etc.
Even without knowing much of anything about DotA 2 in particular: for any game with asymmetric information, the crowd reacting to what your opponent is doing is always going to be a major tell. At least in LoL, managing that information asymmetry is an important strategic element, can't imagine it being any less of an issue in DotA 2.
Later versions of the client added an option to mute those sound effects, for precisely this reason.