By "resort hopping", you mean using your
DVC points to stay at other DVC resorts (like using HHI points to stay at AKL)? As opposed to "pool hopping", which means staying at AKV and using the pool at SSR while you are staying there?
If that's what you mean, then Bill is correct. Those who have read the paperwork agree that blocking resale owners from booking at other DVC resorts while allowing direct owners to do so is probably not legal (myself included). If Disney tried to do this, I'm pretty sure a big lawsuit would be forthcoming. In addition, blocking AKV resale owners from booking at SSR would actually cause huge problems for direct owners as well and would limit direct owners' ability to book outside their home resort.
As Bill says, the guides are just trying to strong-arm you into purchasing direct, and it seems like it's working to some degree.
"Pool hopping", on the other hand, is likely not protected and could probably be taken away, but I think a relatively low value perk.