You're going to get in a lot of trouble in a bunch of ways.
1. When you check in via pager you are acknowledging where you are. When you click on PBI Terminal you've just signed your death sentence if you are somewhere else.
2. Changing a NJA ticket without the company knowso is pretty much fraud. The company has fired pilots for doing the same thing on the return flight. Selling the ticket, getting the cash, and jumpseating home.
3. The company would know pretty much right away. I've checked in and NJA knew I checked in via computer and not at the terminal. No big deal but they needed to change my airline and I had allready gotten my ticket. No big deal just had to uncheck it.
Basically don't think about doing it. Pilots have been fired for not showing up at their gateway before.