I would caution anyone doing this to be very wary. Doing it running around as a 5-man shouldn't be an issue, but parking on a spot and just wiping it out forever could be negatively viewed by Blizzard, especially if they're mobs others are fighting over.

https://www.dual-boxing.com/threads/...ation-Cheating

In classic at the moment, everything seems to be a hyperspawn right now. Anywhere large groups of mobs exist seems to be tuned for pretty rapid repops (enough so that if your team isn't paying attention you can get swarmed under pretty quickly, especially for mana-dependent teams).