Tonymac, not sure if being helpful or just plain scary 
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Well, I'll give an example about this mic thing: we have a few friends who never use the mic, or don't have one. One guy especially was really apologetic for not having a mic/headset, which also made him not able to hear all the convo through tv speakers apparently. He even pondered, if he was welcome to play, because he couldn't talk with us, and he didn't have a chance to buy a mic. We had to convince him many times that it is absolutely fine, we don't care if he just is quiet, as he was a great teamplayer. So you never know, some might take it more seriously, when they really shouldn't worry that much. It's their own choice, whether they want to talk or not, for whatever reason, which may vary.
Also, many just assume I'm one of the guys - until they hear me shrieking when startled by some enemy (sorry guys for your ears..). I don't mind - and not using the mic actually often provides me the chance to play as one of the guys with Pugs for example, without any extra hassle of any kind related to the grilness. (I*m sure Crimson for one can give examples of this stuff for her part..)
edit: And re: Crimson, I meant that she's had her fair share of all kinds of breathers and weirdness just for sounding like a female over the mic. I didn't mean she's given me any grilness related hassle, I should only be so lucky. 