I had one recent similar experience at the Signia Orlando. After entering my last name and room number at the WiFi prompt, I got a screen that said "For free internet, sign up for Hilton Honors ..." As I'm already diamond I just closed the screen. When I asked what was going on, hotel staff just gave me a code which had the word "Premium" in it. I assumed I got premium internet with the code, but never used it enough to know for sure.