It is. OP probably isn't thinking(or cares about, if I were to be cynical) about the people in the group who are peer-pressured into joining (by some of their other 'friends' probably) and are just anxious/awkward throughout but can't/don't want to say anything.
I haven't experienced anyone in my friend group being pressured by others to join into group activities, and I'm pretty perceptive about interpersonal issues.
More commonly what I've seen happen is occasionally two people I'm friends with don't get along with each other, and have negative feelings coming to events/hangs where the other person will be there.
