People leaving early / during cool down

I have noticed more and more than 2-3 class attendees are starting to rush out of class prior to or during the cool down. I realize we all have busy lives and sometimes have to rush from place to place, but some of these people can't saving more than 2 minutes by leaving early.

I am starting to wonder if they just don't think that the cooldown is necessary and that is fine, to each their own, but I would think they would try to just slip out without being noticed. Some of these people are being disruptive during what is the most zen part of class in my personal opinion. This could be because I usually position myself in a corner near the exit or closer to the equipment stations but still.

I guess I will live but I'm wondering if any instructors have opinions on this? How does it make you feel if one of your class attendees leaves prior to the completion of the full class? Do they let instructors know if they have to leave a few minutes early? Is it distracting? I