I can get away with such in certain places, mostly opened to public anyways. I just wave my local press pass, and ask them if I can walkaround for a few minutes, maybe stop at the press pit for a couple of photos and then scoot out to another assignment.
But I have never tried an MLB, NFL, NHL, MLS game. These are the big leagues, with Player Associations, and all sorts of crazy stuff and trade marked names.
Actually I would just let you know that although it is unlikely to happen, if you get in trouble for remotely trying to pass as press, if charged you could get into a heap of trouble. This has been my experience, so I have avoided it.
But best of luck, make sure to have the serial numbers for both units just in case, and post the photos.