When you disconnect from the game by a dc macro, network failure or by alt+f4, your character is still there. Even if you log in back with different character, the former one is still in game. You can even start two clients, log in the first one of them and when you try to login in the other one, you will be DCed in the former.
This can be usefull when you want to help levelling your alt. You can login the alt, move him somewhere where your main will find him/her and DC. Then login with your main or another alt and buff your alt, which is still standing where you left him when DCed. It takes about 30 seconds until your character dissapear.
You can even debuff or kill your alt (for the lulz I guess), if you do this trick in Gurubashi arena. When you DC and log in with different character, you will find the DCed char hostile and you can kill him/her.
This can be actually used to help one of your alts to get Gurubashi Arena Master trinket. Works only on low to mid populated servers and requires a good PvP char! Go to GA with the char that wants the trinket. Position him/her as close to the place where the chest appears as possible. Logout normally. Get your PvP char in the arena as well. At chest time kill whoever enters arena. Try to kill them as far from the entrance as possible. DC and log the first toon. Loot the chest. There is a high chance the killed player will be afraid to go to the arena again if he/she sees you there and it takes about 30 seconds to get to the arena and ress. You have a big chance to make it faster, especially on a fast PC.
For DC macro you can use this (Thanks to hp94)
Disclaimer: It can be considered an exploit.Code:/console startproject