Prior to the new sign going up, this lot was always a nice secret option to avoiding alternate side parking regulations. My dad sure is going to miss it - apparently if you told the guard you were pulling in only to take the train, it was FREE. He pulled this stunt many a weekday when he'd arrive to visit with Pearl between the alternate side hours of 11:30am to 1pm and didn't want to double park and block other vehicles in their spots. I've talked to some other folks who have actually used the lot in the past as a late-night spot to park their car if there was no street parking available. There's always been a sign saying that the lot officially closed at midnight, but I've never heard of anyone being towed over there.
I've gotta say, I'm actually happy there's a sign up now. I hate having to talk my way into situations, and a finsky is quite a bargain to get a parking spot for 12.5 hours anywhere in this city. I also think that if there are Westchester or Connecticut drivers using the lot as a park & ride (as the license plates I regularly see there would indicate), they should be paying for their spots. With all the budget cuts that our 'living museums' are currently up against, it's pretty hard to blame NYBG for trying to capitalize on some prime parking real estate.