We wont be staying in the polynesian next time because its so expensive but we did love it and wanted to use the beach a few days. Is this allowed by disney because I dont think they like people from another resort using pools and things?
The resorts expect visitors. No pool use, as stated, but the rest of the resort is open. Now, having said that, I've seen signs on the Polynesian's Beach saying that it was for resort guest use only.
I don't really know what you mean by use the beach though? Just visit and have a walk along it, or do you intend to do something else? Don't go in the water!