I did get a bill and they add 18% gratuity which Priority Pass will pick up as long as you don't go over $30 (in other words, it's mandatory gratuity, but included in your $30 allowance). Food is a bit expensive for what you get, and drinks prices seem particularly high ($12 simple margaritas), but $30 is still pretty generous. BTW, if you don't get to $30 on regular food/drink, you can add some snacks from their adjacent kiosks to your tab. I think you could also use the $30 at the kiosk for grab and go items (which seems a bit too generous, but I don't make the rules!). Personally, as an AMEX platinum cardholder, I might go to the Centurion Lounge to eat, drink and relax, and then stop by the Corona kiosk for to-go snacks for my flight.