I used to work for a bank where we discovered widespread abuse of corporate credit cards. The stuff we found was unbelievable - shopping sprees, iTunes, even one guy who had been on eBay to the tune of about £3000. Quite a few people got sacked, but what was surprising was how much people denied it when the evidence was right there. I think a lot of people think 'big company, make me work too hard, I'm just getting them back a bit'.