@ A J Stiles Re: Easy way to deal with it

Such a law would be unenforceable; you would need to show that a person could not possibly have acquire a given piece of information from any other source, and it would be very difficult to define what constitutes volunteering information in a sufficiently certain way.

Further, it would act as a disincentive to anyone inadvertently stumbling across something which _might_ constitute evidence of a crime since if they acted on it and it turned out to be innocuous (or even just inconclusive) they would expose themselves to prosecution under your proposed law.

I would also suggest that a person who neglects to write zeroes to every sector of a hard disk before handing it over to a stranger is not an idiot, but is simply not an IT expert.