If you are an owner at BP and using the owner week you booked, your parking is free, if you own at BP but using an exchanged week you pay just like other exchangers. I don't want to defend the decision to charge for parking at BP but right next door parking is $40 a night so BPs charge might be a bargain to some. Ironically, you can park inside the same garage but not on the BP section for a lot less a week. It costs even more than this to park at Custom House in Boston, which is another urban timeshare. in both cases you don't really need a car at BP or CH as everything is walking distance for many people...or a short cab ride.
Brian