If you're being paid by your employer to attend meetings, what phone call could possibly be so important that you can't let it go to voicemail and you get to it after the meeting?
But I'm probably at least 10+ years older than the average person on HN, so maybe that's why. I still remember a time when people who took out a cell phone at a restaurant was considered rude and obnoxious, so I guess times do change.