As
Red Wings suggests, when a crew member is one of the chosen few by HMRC then the whole crew gives them their receipts, properly organised this could show that the 10% sample 'prove' that crew spend approximately 30% to 50% more on meals than they are given as an allowance.
There is nothing unusual in the government looking after itself and servants at the expense of the rest. In several countries, Australia included, on reaching retirement age the DHSS pension is paid and frozen at that rate on that date for ever! However, if you happen to be a civil servant, MP etc. retiring to Australia yes, your DHSS pension is frozen but your Civil Service pension is grossed up to cover the shortfall brought about by freezing. Nice, isn't it? (Sorry, slight thread drift!
).