Heh, I was playing Swede on the EU invasion server near that lovely castle on the lovely hill with the lovely wood. I and many others sometimes charged towards the bot spawn and then returned to the player spawn. Twice so far a cannoneer there fired at the bridge which was full of players. I can understand accidentally killing teammates while blasting enemies, but the bots weren't actually there yet.
Edit; irt Rath0s. Indeed strange that the gun went off when you clicked in the log. With a normal weapon it doesn't make an attack either so it oughtn't with cannons.