RISKs of munging DST

The previously mentioned plan to change when DST is in effect was also mentioned in the latest RISKS digest, and the author points out an aspect of the plan that will be especially problematic:

Regardless of whether you actually think daylight saving is a good idea, there are definite risks when you decide to change the rules on how it works. In this case, the proposal is to have the change take effect this fall. I'm curious if Congress realizes that just about every single computer system would have to be updated so that it would keep the correct time.