It's not a good idea, mainly because there will be a false security from thinking you'll get more. You probably will get more, but we've learned something from public health. There are declarable, mandatory reportable diseases, such as tuberculosis, diphtheria, and malaria. There's a list of 16 or so. The problem of under-reporting them is so huge that public health officials have worked out fairly complicated methodological approaches to assess and inflate the under-reported figure. That's number one.
Number two, courtesy of bioterrorism in the United States they're moving to a whole new way of attempting to detect emerging epidemics. It's probably not as good as you might hope it will be. If in a declarable disease like diphtheria we can't get our act together to declare it, just imagine how it's going to be for adverse events for drugs.
I would rather put the investment in something else, like a systematic surveillance system.