Flutterby™! : Damned if you do

You Can Be Prosecuted for Clearing Your Browser History:

Prosecutors are able to apply the law broadly because they do not have to show that the person deleting evidence knew there was an investigation underway. In other words, a person could theoretically be charged under Sarbanes-Oxley for deleting her dealer's number from her phone even if she were unaware that the feds were getting a search warrant to find her marijuana. The application of the law to digital data has been particularly far-reaching because this type of information is so easy to delete. Deleting digital data can inadvertently occur in normal computer use, and often does.

Chilling.