An extract from the World Naked Bike Ride book:
In terms of any WNBR, the police will always be involved to some extent, for no other reason than that the ride is firstly and foremost a political and environmental protest. A police presence, involving quite probably some form of prior consultation concerning routes, traffic disturbance and control, other (perhaps opposing) protests, is almost guaranteed for this reason alone. The fact that there are likely to be naked people participating in the event merely serves to heighten everyone's interest, which you'll remember is of course the reason for the nudity in the first place. Whether the police feel the need to suppress nakedness, as in Paris, or as regarding Gough in Scotland for instance, experience shows that to the public themselves nudity is very often entirely acceptable in this day and age. Indeed, while John Stuart Mill may not have had public nudity in mind, the principle which he described still stands: "The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant."