Commerce includes many unspoken agreements. Order a meal at a restaurant and expect to pay list prices +taxes etc, you don’t expect to be charged for using the salt on the table, or the price of a doggy bag etc. Airlines don’t charge people to go to the bathroom, though they may reserve better bathrooms for first class etc.
Companies breaking with these trends face a backlash assuming a competitive marketplace.
Reasonable is not wanting to be nickle and dimed for every amenity that could possibly be split into a separate cost.
Prices for such add-ons, especially ones that your average customer won't think of before, are also often unreasonably high because the operator knows they have a captive audience they can exploit - you either buy from them or go without.