I am in sales and do a lot of road trips for my job. There are many times where I am not sure which set of customer meetings will get confirmed until the day of the meeting. Being able to book multiple reservations with a 6PM cancellation time has been very useful to guarantee myself a place to stay regardless of how my meetings turn out. I try to be good about it and cancel the unneeded reservation(s) as early as possible in the day. A comprise that would still work reasonably well for me would be to move the cancellation time up to 3PM or 4PM local time. That would give the hotel more time to resell the room and still give me enough flexibility. The day before is too early, since I may not have my schedule finalized until the morning of the travel day.

--Jon