I think your friend may have a misunderstanding.
I do not work for Virgin Atlantic but know for a fact she will be on salary.
Money received at the hotel is their allowances. Most airlines pay you a per diem, which is a living away from home allowance, and includes living costs plus incidentals. Some airlines choose to deposit this into your bank account where as others may make it available to you upon check in, in local currency. This has nothing to do with your salary, and should have no affect to your yearly earnings. If she is smart she should be able to live off the allowances and save her salary, thats what most of us do, the allowances are huge in some ports.