I'd be, in my mind, be playing tribute and thus play my heart out if my band covered Sabbath's Into The Void even in a small gig.
Baka it has a lot to do with the perceived sincerity of the band. Some bands, you'd think are just doing covers for the money (and that they lack creativity) but some bands, you'd think they're genuinely paying tribute to a really great song. Cueshe and bands lumped with it... I'd perceive to just be doing it for the money. Meaning, I don't think they're sincere in music. Bamboo, neither. Rivermaya, I'd probably give them some credibility. But that's just me.