Just like CS and many other games, we should have the ability to spray a tag.
- Legacy ID
"I'm curious why this was down voted so much?"
Most likely that people don't want this to be something like "Valve" CS kind of game? For my part I think it could be a good idea, but maybe make it something that represent the game? Maybe warning signs for infected areas and similar.
The idea itself is good and I vote this up :)
Freehand spraying would be nice. Tagging looted houses, spraying arrows on tarmac, etc. But I'm afraid it will devolve into all walls being covered with "[KOS]l33Thaxx0R420nosCope wuz herr lulz" :P