On my sniper and my PT I wind up guarding a lot, more than I would prefer but if I get left behind I'll suck it up and guard. As soon as I start guarding I always pretype the call in my ops chat and click outside of it, that way as soon as I see an enemy coming I hit Enter twice and the pretyped message is sent.
The other day on my PT I was guarding a pylon in hypergate and had my pretyped message ready to go, I had even noticed 3 stealth interfering with our taking of the pylon and let everybody know about it, saying it would be best to leave at least 2 guarding that game at all times due to the stealth factor. Not even 15 seconds after I tell everyone that they all leave me at the pylon by myself so they can go kill people at mid. I knew what was about to happen. Sure enough, 3 stealth open up on me (3 deception sins mind you) and I call immediately with my pretyped, ready to go notice to everyone. After two or three GCDs, I am dead. We lose the pylon which causes us to lose the game. Then the hate begins..."L2P noob, call before you are dead". Idiots everywhere.