For me, it depends on the meeting. I, too, listen better when my hands are in motion - otherwise, I tend to be distracted, get fidgety, etc. But I won't knit it I think people will be offended, or if it seems like my knitting my distract me, or if I'll be doing a lot of talking at the meeting, or if the meeting is very small and my knitting might distract someone else.
This week I went to a Trustees meeting at our church. For the first hour, I didn't knit. But after an hour of listening to all the minute details of buildings, grounds, and finances, I couldn't stand it anymore and had to break out my knitting. I had brought a sock, so it was small and discreet. I kept it in my lap rather than out on the table in front of me. The people at the meeting, mostly men, didn't seem to mind (some of them didn't even notice). Afterwards a woman at the meeting asked what I was knitting and told me she thought it was a very intelligent thing to do (knit at the meeting).
FWIW, I'm the pastor. Sometimes I'm the one running the meeting, and I never mind if I see someone else there knitting. (I even saw a little girl knitting once during worship, which I found very endearing).