nope they are not. I mean I have seen my cleaner get a little PUNCH from an anenome tentacle I am sure it does not feel good but it did not kill them. I am sure if the anenome got a chance to engulf the shrimp I would say he would ge a gonner but a little brush wont kill them but it will make them know they are alive that is for sure
Mine steals food out of the nem, too! He did get zapped one time during his "lunch" ... poor shrimp jumped about 3" backwards in the blink of an eye! He has been a little more careful aorund the nem since.