If you hide something, does it not follow that you have something to hide?

How can Ann Romney say that Mitt has nothing to hide? He is not divulging his tax returns and so ipso facto he is hiding his tax payments. I suppose she means that he has nothing to be ashamed of. Among a group of fellow robber barons, he might even be able to point out with pride how he used loopholes to lower his taxes. Those who make less but pay higher tax rates (which is just about all of us) may not be so amused.