I've seen this mostly on regional rail, but I know this is an occurrence on PATCO too. You're sitting there catching up on Twitter, or possibly reading a book (I think people still do this) when you think that your stop has already approached. This is due to the fact that there are now no less than 10 people standing in the aisle. But wait, it's 7:44 and the next stop isn't until 7:51.
This is completely unnecessary though. In my experience if you stand up once the train actually stops, it is the people behind you who bear the responsibility of letting you go. I would think this line of people who have been standing since North Broad would want to reap the benefits of their premature seat evacuation, but they are surprisingly civil at letting one get out of their seat. For this reason, if you are one of those people that stands up five minutes before your stop you are really only doing yourself a disservice.
Still, keep standing, early risers. I can't imagine how awesome it must feel when you burst through that imaginary tape at the finish line and exit Market East/Suburban/30th St. Station a whole 15 seconds earlier than your competition. I wish I had a job I was that excited to get to.