Hiding faces is always a tricky one. You want to do it without ruining the photo whilst also making absolutely sure that your identity is kept secret. You also need to consider identifiable skin markings and tattoos and the background of your photos (you don’t want to catch a family photo hanging on the wall).
There are two main ways to approach hiding your face, either obscuring it in an graphics package afterwards and, the old-school approach, wearing a mask or improvised face covering. Wearing a mask, especially for outdoor nudity, protects you from neighbours and passersby catching you naked, photographing you naked and posting it online. Another advantage with the mask option is that it works in videos too. However, it could also make you look like some kind of weirdo and potentially threatening (raising the possibility of someone making a complaint). I’ve also heard people say that wearing a mask lessons the feeling of being naked and exposed.
If you opt for modifying the photos after the event, I recommend blacking out the eyes and nose at minimum. Don’t be tempted to use distortion or colour effect – they can be undone by a skilled operator.
Another simple technique is to simply keep your face/head out of the photos. This is easier to do if someone is taking photos for you. It would be great to hear if any of you have tried out any of the above techniques.
I guess the easier approach is to simply let everyone see your face but I know many people won’t go for that.