The predictable irrationality of ethics - why we find it more difficult to steal money

I read Dan Ariely's fascinating book 'Predictably Irrational' last month.  It gave me a great deal of insight into how we make irrational decisions, but more importantly how we can understand (and perhaps even predict) such blunders.

In chapters 11 and 12 of the book Ariely deals with the matter of ethics and morals.  He shows through a series of experiments how we make unethical decisions because of the way in which our brains value different things of the same value...  Perhaps you should read that sentence again?

Simply stated, let's say a Coke costs US$1, what is more valuable to us, the Coke or a US$1 bill?  Well, he conducted an experiment where he placed 6 Cokes in some University dormitory fridges, and a plate of 6 US$1 bills in other fridges.  After 72 hours he returned to see which of the items (the money or the cokes) were stolen more easily.

It is not surprising that he discovered that in almost all the cases the Cokes were gone, but the plate of money was untouched in almost every case.  

In short this experiment (and a few others that he uses to verify his assumption) shows that people are less likely to 'steal money' than 'steal coke' - why?  Well, there seems to be a far greater social stigma attached to taking cash than there is to taking objects.

Here's another example.  Let's say you're at work and your wife phones you and tells you that your child needs a pencil for school.  Would you feel OK -> Not too bad -> Too guilty to take a pencil home for her? Most people answered that they would feel OK to take a pencil home.

Now, let's say that there are no pencils at work, but there is a shop downstairs that sells pencils for 60cents.  The company's pettycash box is in your possession and no one is checking.  How would you feel about taking 60cents from the pettycash box to buy a pencil for your daughter (the value of the pencil you would have taken from your company is 60cents)?  

Most people indicated that it would be much more difficult to steal the money than it would be to steal the pencil from their employer... 

Why?  Well, we have been socialized to think that money is 'worth more' than goods or time!  People go to jail for stealing money, but we seldom hear about people going to jail for 'stealing a pencil', or 'stealing time', or 'stealing private phone calls' from work...

I was fascinated by this (predictably) irrational element to my own ethical decision making.  What do you think?  Is Ariely's interpretation of his findings correct?  Is the value of goods and time the same as the value of money?