dont ask me why i know this !
polices drug dogs go abit funny when they smell the paint out of a paintball so i wouldnt have any in ur bag that might brake ok
What? You are not going to set a drugs/explosives sniffer dog into attack mode cause you have some paintballs! You've had this happen have you?
We have had mixed experiences. Most times we just board as normal, and everything is fine. A couple of times we have been asked to explain and show them whats what, and once you have shown that there is no pressure in the bottle, they always are fine. They never really seem to worry about the gun.
Good tip is to put your bright sporty playing top and a PGI in your bag to back up your "Im not a terrorist, Im a paintballer" likely story.