How Does a Reader Read What it Doesn't Know is There?

If a tree falls in the woods... I know... but this is a serious question. Never mind all the pseudo-psycho-privacy paranoia in this article about travel cards, RFID and border crossings... here's the part I don't get:

Homeland Security has said, in a government procurement notice posted in September, that "read ranges shall extend to a minimum of 25 feet" in RFID-equipped identification cards used for border crossings. For people crossing on a bus, the proposal says, "the solution must sense up to 55 tokens."

What if there are 56, 57, 58 or 198 people on the bus and one, two, three or 143 of them just decided to leave home without it... the ID card I mean? And by the way, can't I just borrow Hector's card and mail it back to him when I get to Fresno? Is this going to work?