The one at FW is for anyone, and I'd assume that the one at POR is as well. Unleses they start to get too full where resort guests complain, I don't think they'll restrict them. I don't think the one at FW is ever really that crowded. Keep in mind that during some of the busiest times it's either REALLY cold out, which keeps a lot of people away, or cancelled due to inclement weather or mosquito borne disease issues. If you're attending from another resort, I'd call before making the trip.
Anne