I have definitely had cases though where I've run into "Where did this subscription come from?" and there was no apparent way to cancel. Last was something Yahoo-related a number of years back. Ended up doing a chargeback and canceling the charge.

I would absolutely chargeback in this case. Some non-standard clause WHICH THIS ABSOLUTELY IS RELATIVE TO HOTELS (OR EVEN REGULAR B&Bs) buried in T&Cs somewhere should not be acceptable.