I've never been charged for receiving a package at any Marriott-branded property. I'm sure, however, at least some properties would just love to try it.

My guess is what happened at BNA was simply a routine attempt to shake down the customers for as much extra revenue as possible. I'd further guess that they typically drop the charge anytime a guest complains. But probably there are enough unwitting people who blindly accept this ridiculous fee so as to enable the hotel pick up an easy few extra hundred bucks a month.