For that particular stay, yes. But it increases the likelihood that the customer will come back and, perhaps more importantly, tell everyone they know about how awesome the place is. It's hard to see how this wouldn't work out to a net positive in the longer run.

So yes, if this were an additional $20 per sale it might deeply cut into their margins if they aren’t a luxury product.

However, I struggle to imagine that every, or most, or even many, of a hotels sales are anniversaries, or similar kinds of events, that would deserve such additional servicing.

If the total profit is $200k, a single $20 (or relatively few) instance is nothing, regardless of high or low margins.

Specially servicing these rare, one-off events, is exactly how you exceed customer expectations without running your business into the ground.