That was explained by Chris Mac Donald in his Health Law Review paper. Here's a quote:

Cheap, high-quality, unobtrusive surveillance equipment of the kind promised by nanotechnology is likely to lower the costs, and increase the benefits, of invading other people’s privacy. We can reasonably expect that the availability of such technology will make it harder to maintain current privacy conventions. You and your neighbours may thus become tempted to shift from a pattern of behaviour under which you both respect each other’s privacy to a pattern under which you both invade each other’s privacy. After all, you’re both likely at least to be tempted to eavesdrop or sneak a peek, once in a while; and besides (or so you may reason), if your neighbour is likely snooping, why shouldn’t you too? Nanotechnology, then, may work to corrode extant social conventions – ethically useful social standards – associated with privacy.

Read the full paper yourself here.