Non members use those pools all the time, either as cash staying guests or as guests of DVC members.
What we are really talking about is hopping. DVC members can hop, others can't. Its hopping for a FW guest to come over to the WL - therefore against the rules. Is it hopping for a BC guest to use the BCVs quiet pool? I think you'd have a hard time making a case for that. Disney doesn't seem to think it is - as they have all the pools marked on the maps with times for guests at the "hotel" portion of these resorts.
The next question becomes, are they subsidizing the amenties for hotel guests using our dues? Don't know. Is it a big enough deal to care? Don't know. Strikes me as the kind of thing it takes more money and effort to look at than it would solve (unlike bus transportation - which is a fairly major expense).
If I had to guess, and I, of course, don't know -- I'd guess that pool maintenance for the hotel/DVC resort as a whole is paid for on one line item and then prorated and billed back to DVC based on the proportion of rooms - there would be no seperate break out for our "DVC quiet pools." If this is the case, we are probably getting a pretty good deal - as I'd guess us frequent Disney guests use the pool more often than the occational Disney commando.