Our guild Rogue Angels (US Guild), while we don't pug very often, but when we do, we do not require aa/exp/gear. With that being said, you never know who is going to join and I can say we've had players from both ends of the spectrum. While we don't mind explaining things, some people choose NOT to speak up when they don't know what to do, refuse to get in Vent, and end up causing a wipe.
I used run a Pug T3 on Sunday nights and occasional t1/t2 raids. I took whoever wanted to join regardless of exp level. While most were good listeners, I think I only kicked 3 people in a 2 year span. People that blatantly don't listen, consistently screw up, and just waste time is why the reason most guilds ask for experience. They just are tired of bone-heads.
I remember that Vistrix raid. The dude was adamant about someone turning the dragon and was in true disbelief when it went down that was pure Luck. People can't stand to see different strats work or are so used to the lazy strats to prevent paying attention.