Chances are that the owner is well aware that few people who cancel will do so before the deadline. But, he believes that he can rent the place again on very short notice and so long as he gets more than 50% of the rate he charged the first renter, he is making a profit off the cancellation.

"Walk up" rates are often very high because people are desperate for a place and can't commit early. So, my guess is that for a high-demand property, this has all be thought through and the owner could care less whether you cancel today or 8 days prior to scheduled arrival.

This is just another one of these misdirected hatred threads. If OP has a properly scheduled vacation and his employer requires him to cancel, a decent employer will pick up the various non-refundables as a matter of course. No reason for the property owner to step in for a lousy employer.