As an analyst in my day job, I'm simply using all the information available to me. These job postings make it appear that they are paid a decent fixed wage. My own observations of tipping behavior, as well as the stacks of cash on and behind Centurion Lounge bars, and the lack of turnover at the lounge I go to most frequently leads me to believe that they are compensated to a point that they're happy with. And to use the starving term literally, every staff member in a CL appears to be well fed, some more so than others. I presume they get free meals when on duty (as the job posting I linked says, at least in SEA).