Thanks for all the replies.
Yes, my employer reimburses travel expenses. In my past jobs for European companies and Government related corporations, there have been a per diem allowance from which you pay for the travel related expenses.
I think the per diem method is more convenient as there is no need to keep lots of receipts and then having to spend a good part of a day to account for them all when you get back from longer trips.
The issue is not trying to profit from an allowance, but having it set at a reasonable level that reduces unnecessary paperwork.
From the responses here, it seems there are companies in each camp with no clear dominant policy position in industry regarding this issue?