GvG: GL ganking and ninjaing, What's the counter?

Currently a lot of guilds out there are farming for faction by tanking their guild rating, then doing random matches against n00b teams. What they do is try a quick rush at the guild lord. If the rush doesn't work, they leave the game and go off to the next game.

So, how do you know the rush is on?
Someone mentioned counting the number of enemies you can see. If they all aren't accounted for, they might be trying a rush.
Post a scout at the back/side gate. I guess someone with sprint/storm chaser/etc so they can run back if a rush isn't being done. Maybe some snare skills (barbed trap) would be good to slow down the enemy if a rush is under way.
All of a sudden your GL's health starts dropping [not good!]
Anything else?

If you know the rush is on, what do you do? Run back and defend your Guild Lord? I'm thinking rushing theirs isn't a good idea since they have probably practiced rushing a lot and have a build set up to be able to take down a G/L in short order. We probably aren't prepared to "out rush" a ganking build. http://www.theamazonbasin.com/gw/forums/index.php?showtopic=2571