Leaving aside the puerile sniping that will undoubtedly follow the post from juliet, the concept of reimbursment for justifiable out of pocket expenses doesn't seem that unreasonable to me as mere civilian filth.....
Until you consider the practicalities. Specifically who would pay the cost of the 'actual' expense - and when. And who would justify it?
Nowadays if I travel somewhere, the company pays for me to drive to the airport, park, fly to wherever, stay overnight and the same coming back. Plus any meals I might pay for. Easy enough, just send them the breakdown every month. OK - fine for one person and a company which trusts you and isn't spending taxpayers' money directly.
But to settle a Service bill with every single item fully receipted and identified.....what joy for the FSI holder. Perhaps juliet's auxiliary crew station will soon house an Air Adminer with laptop to account for every actual penny spent?
"OK - who didn't have rice...?"