My experience with being squelched came from a bloody crypt run where we were ready to pick up the thing to complete it for something like 20K xp and the leader wanted to go get all the breakables in the entire west wings for the additional 5% ransack xp. If you know anything about the size of Bloody Crypt it gives you a good idea of the type of people we're dealing with here. I said no we're not waiting to get the additional 5% xp (300 xp?) and completed it.
Lo and behold I landed on that guy's precious 'squelch' list. To this day I sometimes hit his LFM's by mistake and get auto declined 5+ years later.
It tells you alot about the "squelch" list and the types of people who use it.