Re: Having your own computer means never having....

I can't think of any real security risks introduced by allowing
	 employees the use of encryption, that weren't present already.
	 Certainly none mentioned thus far fit the bill. 

Have a look at Matt Blaze's paper from Usenix last week.  He describes
a smart-card based key escrow system for file encryption -- the risk
to the company is that an employee will quit, forget a password, walk in
front of a truck, etc. -- at which point they're unable to get at the
files that this person created -- files that the company owns in
accordance with the provision of the free-market contract willingly
agreed to by this employee.