In my many searches for Hilton Group properties around the world I have come across a few non-participating hotels. One that springs to mind is listed as "King Hussein bin Talal Convention Centre managed by Hilton" in Jordan, although I am sure there are a few others as well.
I have never fathomed out why this would be. Why be a part of the branding but not take part in the loyalty programme. And why would Hilton (Honors) allow this?
Could it be that in the case of the W-A Palm Dubai that the property does not YET participate, as it is not accepting reservations of any kind? It may well be that the property has to become registered in the programme and that when reservations open this changes ...