This is why I'm a HUGE believer in the pre-emptive strike. I usually volunteer for about 10 minutes or so, then I'm done for the class, unless something being said is particularly interesting.
So, riddle me this, batman...
How does volunteering for 10 minutes, and then not saying anything for the remaining 1 hour 5 minutes plus, make me a gunner?
A gunner is someone who talks all the time, usually with no point to what they are saying, other than to hear the wonderful sounds of their melodious voices. Clearly, If the total class time is 75 minutes, and I volunteer for only 20% of it (at most), that would leave wholly 80% of the class time where the only communicating I'm doing is on IM.
If you think that makes me a gunner, maybe you are projecting your own "gunner-ness" upon me. Maybe you're the type who has to say everything, all the time, and hates whenever anyone else dares to answer a question in class, because they clearly don't know the answer, because they are not nearly as brilliant as you are.
1 person in a class of about 90+ taking up 20% of the time is a little disproportionate dont you think? And as most of us know, after grades come out after that first semester, a lot of gunners seem to learn their place.