Urederra
Mostly harmless
In fact, at least in Spain, nudism is TOTALLY LEGAL IN ANY PUBLIC PLACE can be beach, river, park or street.
I didn't know that, although I have seen nudists several times in a beach in front of Argiñano's restaurant, where there are no signs warning about a nudist beach or fences separating a normal beach from a nudist one.
And nobody complains about the more common topless practices in any Spanish beach either.