Have left every guild that has spammed me with these notifications.
"If you want others to be happy, practice compassion. If you want to be happy, practice compassion." -- the 14th Dalai Lama Wisdom is doing Now that which benefits you later.
I don't even care if their is a toggle option but please turn it off, sometimes I play eso on speakers and nothing is worse then getting blasted with "booommmp" every five minutes because my guild is doing trials.