If you're talking about booking several days before your intended arrival just to get a jump on bookings, I don't see how that's any more opportunistic than what people have done in the past.
Even though it was a practice endorsed by DVC, one could argue that day-by-day bookings was taking advantage of other members. All of the guidelines distributed to members state that reservations should be made 11/7 from the checkOUT date.
People book days they know they will later cancel because they aren't certain of exact arrival and departure dates.
People book multiple unit sizes knowing that one will later be canceled because they don't know how many will be traveling.
People pre-book dates strictly for rental purposes--and I'm not talking about these so-called "commercial renters."
Regardless of what reservation system is in use, people will learn how to manipulate it to their greatest advantage. In your case, ultimately you will be keeping only the days that YOU actually want, and the rest will be released to other members. I don't see that as causing any more harm to members than the other forms of abuse that already exist.