Correct me if I'm wrong but the Flight Crew have two tier rate? One for sitting ona beach (or in a hotel room), and one for flying a jet.
Not really correct, in that the pay element for flying does not replace the TAFB element, it is additional.
The TAFB is paid from check in to check out at the end of the trip and replaces allowances. The Flying pay element is paid for flying out done. As most pilots fly the same number of hours per year, we all earn the same flying pay element, so we don't really care where we fly to as far as money is concerned.