I haven't seen this suggestion yet. Let us set the music/ambient/whatever sound to change when something happens, say after an objective is completed. For instance if I talk to an NPC in a quiet peaceful area I can set quiet background noise to match, then after I finish talking to that NPC, hundreds of enemies attack...…
Plenty of gold spammers hanging around the market area all day, not only that but I received 3 spam mail messages from the same bot while I was logged off. So they are spamming using the mail as well...
Only had a player drop out once but it was right before the last boss of the dungeon (and we were tearing through it so I don't know why the left) Luckily we still took it down due to a great healer, so no big loss.