It is a perk to have it mailed back for free but is not to be expected at all.

To expect it and to think the hotel is doing something wrong to not cover the shipping is way off base in my opinion.

I have left things multiple times over the last decade, have always offered to pay for the shipping (lifetime plat) up front and have had the fee waived most of the time.

When it was not waived I was perfectly fine with that as well.