I have run into the T-Mobile hurdle, or speed bump, at several Hyatts and Hyatt Places. Sometimes it has just been my error to sign in that way, and sometimes it has appeared to be the only path to wireless. In either case, it appears to be just an inconvenience for the front desk to remove the charge.
And, JonathanIT, I have thought that HotelNet at the Hyatt was actually another nearby hotel's signal. Back in the day when we did have to pay for the Hyatt's signal, I was grateful for it and also what I think I remember was the Hilton property's free signal. Before the construction, I used to ask for an atrium room because all the signals were|are better on that side.