Number of times i was invade while in Way of the blue: around 20
Number of times i had to fight them off by myself: around 30
Blue Sentinels gotta do their jobs man.

I've been summoned to help Way of the Blue'ers several times before but the way the whole thing works could have been so much better.
I have to be human, have the ring equipped and be in a "multiplayer friendly" area. So if I'm in Majula I can't be summoned, even though the summoner can be anywhere. Often I don't want to waste the ring slot or I'm not even human. This makes it so I can barely save anyone.
Once I finish the game I'll dedicate some time to stand somewhere I can be summoned and just wait.