Context here is important. Does it mean if the hotel isn’t booked in a reasonable time you should just go for a suite at the Four Seasons with a spa package, certainly not.

Being in this situation I would pull up the SPA approved hotel list and start there. If it’s a weekend or holiday or convention, the walk up rate for that day may be significantly higher than other times, but the company would have little grounds for protest if it was shown they had ample time to make a reservation but neglected to have it ready and the chosen hotel is on that list.

If there is no vacancy at any approved hotel, I may do a cursory search of similar quality hotels to those on the list, but if the choice is between an $800 airport Marriott or a $100 Motel 6, well they can leave the light on for someone else as the due diligence in this situation is the approved hotel list and a call to a chief.