Many hotels have started charging resort/amenity fees for guests as well. Traditionally commissions were only calculated on base room rate, so making up a mandatory fee and shifting some of the rate over acted as a super handy "tax dodge", artificially lowering the commission owed to all their booking partners. The same applies to pre-negotiated corporate and event-block rates – they can win business with an artificially low price, then pad the actual margin of stays via an ambiguously defined and undisclosed but "industry standard" destination/resort/amenity/urban fee.

Between that too-easy-to-pass-up profit optimization, and the marketing benefits of deceptively low list price, it's become pretty pervasive. And isn't limited to actual resorts – I've had bog-standard business hotels in the suburbs tack on a $30/night non-waivable "destination fee". Luckily it got to a ridiculous level recently, triggering a lot of media backlash and class action lawsuits last year[1][2].

It's also losing effectiveness, as things like online booking websites start displaying all-inclusive pricing and renegotiate their commission structures to be inclusive of mandatory, non-governmental fees. Between that, all the negative sentiment, the spate of lawsuits and legislation its triggered, the fees are hopefully on their way out.

[1] http://killresortfees.com/

[2] https://www.cnbc.com/2020/02/07/resort-fees-being-addressed-...