Civvy charter has been used extensively in Libya some paid for by employers such as bp and some by the foreign office which the pax will have had to pay for!
Well done for mentioning BP - they are a professional company, who employ competent ex FCO and SIS personnel as their strategic security advisers, competent ex-Army officers (usually about Colonel level) as their tactical planners who put in place contingency plans for all their vulnerable installations, competent WO1s as local executive officers to carry out those plans at each location, and loads of ex RM/Para junior NCOs as on-site security officers. As you say, they have planned properly and are paying the correct commercial price for evacuation.
Unfortunately, there are plenty of oil companies who have not put in place professional contingency plans because they didn't want to pay for professional servicies and did not want to pay for insurance - and now the RAF is coming to their "rescue" to great public fanfare. The RAF should take into account the penalty paid by well-run companies before they subsidise badly run companies - that is why I suggest they set up a commercial arm.