Originally Posted by
Wolfie
It was basically the lowest level of safety net that guilds could enforce because it was easy to install, use, and understand.
It aggregated clear warnings that the boss gave, like emotes and shouts, with timers that had to be thoroughly tested by the top raid guilds (reason why DBM warnings were always 1-3 weeks late after world first kills on bosses).
Functionally it's no different than having a raid lead yell at you over Skype/Mumble/Vent about what you should be doing or paying attention to. No amount of yelling or DBM warnings are going to move your character for you, and you are neither a worse player for following them, nor a better player for ignoring them.