Note that the T-Mobile day pass isn't just for that CRC; it's for a day in any CRC, so after you first pick up the pass, as you travel from airport to airport, you just pop into the CRC and log on. I do believe that it's only free for CRC members, but not for others (i.e. not for E+ on int'l itineraries or Amex Plat card holders or partner airline lounge members).

On more than one occasion I've gotten the card in the morning at ORD, then logged in again at ATL centerpoint, then moved to E concourse and logged on there, or to a third airport and logged on.