I got a reply from one of the Hyatt hotels in London via email after I sent a message stating how surprised I was to see this fee show up as a note in the confirmation email. Here is the key sentence in the reply from the hotel:
These charges are discretionary and if you are refusing to pay them the Hotel will remove them upon Check out from your bill.
Yes, I guess that is what 'discretionary' means but thank you in advance for putting the onus on me to have your surprise fee removed from the bill which was a total surprise to me. I don't like this policy, at all. And what if I use the mobile app or email to remotely check-out, will the hotel make it easy to remove the fee? Somehow, I doubt it.