Take the case of a well-known IT outsourcing company. They had a star salesman who brought in contracts worth literally millions. Like many successful pitch artists, he had a trademark. His particular leitmotif was his Texan cowboy hat. Perhaps not the style that we FDs would choose but it takes all sorts...

One day, as he lunched al fresco with a highly promising potential customer, the salesman's ten-gallon was blown away by a gust of wind. Rather than chase after it in an undignified manner, he left it to blow into the road where it was crushed under the wheels of a passing lorry. He laughed it off, of course, and it's sure to have fixed him in the client's memory.

Naturally, the salesman bought a replacement – and on the grounds that it was damaged while he was working and that it was an integral part of his sales pitch, he added the headwear to his next expenses claim - which was paid, minus the cost of the hat. A curt note from accounts informed him that "apparel could not be purchased on the company's account".

This signalled inter departmental war. Determination is a key characteristic of both sales and finance professionals. So when, a month later, the hat was back on the expenses form, it was duly ignored. The following month expenses were submitted – without any sign of the hat. In its stead was a note from the salesman informing accounts that he had once again claimed back the cost of the hat but now they had to find out where he'd hidden the amount.

The moral? Companies need to have a grown-up approach to expense claims – and sometimes you need to look at the overall picture rather than the petty rules, no matter how carefully documented. (In this case, of course, the smart thing would have been for the head of the salesman's department and the FD to finesse the issue over a lunch of their own. Sadly, the juniors in the finance team were a bit hide-bound...) If accountants know one thing, it is that if you make a rule, some people will make it a point of honour to try and circumvent it.

Another example: a former colleague paid me a visit while I was working in the US finance department of a multinational. Meeting me in my office, he observed that I made extensive use of Post-it notes to write reminders to myself. He told me if I wanted to work such a system in his office, I'd be buying my own Post-its. Someone in finance had worked out how much the company was spending on the things. So the stationery cupboard had been emptied of them. They were still in wide use, of course. Employees just gave the office junior a few dollars and sent them down to the stationery store where they purchased a pad or two at a time. The purchases were claimed back ….. on individual expenses forms.

This was madness on three counts. First, the time wasted by staff buying their own office supplies. Second, the cost of individuals buying Post-it notes at retail prices rather than taking advantage of bulk discounts. And third, the cost of processing the additional items on expenses claims.

Clearly, no one would agree to a no holds barred expenses policy – you'd get a lot more than a ten gallon hat on there (although the UK hospitality industry might get a shot in the arm). That said, some argue that above a certain level of seniority, managers should sign off on their own claims – subject to random checks and verification, of course.

But whatever the checks, companies have to make sure the cost of the expenses monitoring system does not cost more than the expenses themselves. One company I worked for had modified its accounting system so the sales director could monitor claims not only by employee, but by grade of sales staff as well. What useful information he hoped to derive was never obvious. What was clearer was the amount it cost –around £10,000 at installation and an additional £5,000 to keep it up and running whenever the system was upgraded. In total, more than the likely savings from reduced expenses claims.

Sledgehammer bureaucracy can compound the cost. My current bed-time reading (it has certain soporific qualities...) is the travel and expenses policy of a well-known organisation. It runs to a mind-numbing 25 pages, including one page devoted to the 15 different categories of staff travel and subsistence. Are this group's expenses claims ever completed to code? I doubt it. This, as we know, is not atypical.

We are always being told to keep a lid on costs – and finance has a central role to play in this control activity. But resist the temptation to hammer anything that moves. It's rarely the best policy in the long run. Aggrieved salespeople may end up looking for employment with less enthusiastic nut-crackers.