We pool hopped on our recent trip to WDW, June 21-June 29. I called ahead to the Poly about using the Lava Pool there with the nice slide. We were told to come on ahead and have fun. No problems at all. Called Yacht Club about use of Stormalong Bay, told to come ahead and enjoy also. No problems whatsoever.
I think the key is to call ahead so that there won't be any surprises.