Be sure to familiarize yourself with BoatyBall, as most of the moorings are now reserved and/or paid through them. Some fields have their own systems. Guys who collect cash in a dinghy are fairly rare, as are FCFS balls. The week after Christmas is very busy, and places like Cooper fill up fast.
Cruise ships have taken over the BVI, with upwards of 12,000 people on some days, especially that week. This has caused a real problem in places like the Baths and White Bay, and made Anegada more popular.