I've sent two messages to the O'Hare Parking people, asking what's going on, but have had no response. There is info about a "cell phone lot" at F, that wasn't there yesterday. That text says:

Cell Phone Parking Lot

O’Hare International Airport now offers a Cell Phone Lot for motorists waiting to meet arriving passengers. Motorists will be able to park in the lot at no charge and wait for a call from their arriving passenger before driving to the front of the terminal for pickup. These convenient waiting areas eliminate the need for circling the airport repeatedly if an arriving party is later than expected, ultimately resulting in less roadway traffic and congestion, less air pollution, and increased auto fuel savings.

The 150 space lot is conveniently located at Economy Parking Lot F. Exit I-190 at North Mannheim Road, and follow the signs to Economy Parking F/Cell Phone Lot. The lot is located less than four minutes from the Central Terminal Area and easily accessible by all motorists.

Vehicles in the Cell Phone Lot must be attended at all times. Violators will be ticketed and towed at the owner’s expense.

Lot F was closed after 9/11, ostensibly because it was "too close to the runways" which has always been a mystery to me since E and G are clearly closer. I've seen F used upon occasion as overflow space, but it has been generally closed. I'm not surprised they're using F to replace E, but I'm still mystified by the lack of information.