If Knudnuts takes your picture and doesn't obtain a signed release from you, he may wind up violating publicity laws (not the same as privacy laws). Basically, he can not use your likeness to promote a product, service, or idea without your permission, even if the photo is taken in public.
For instance, if your photo is shown in an ad or presentation for stricter gun laws or range rules, you are now associated with the idea he is promoting. Just like a Republican's picture taken in a public park can not then be used in a Democrat ad without permission. You are not required to have your image be used to further another's cause without consent. If you are not doing anything illegal or newsworthy, you have a say in how your likeness gets used.
So, if anyone's faces are made public to support his quest to close or restrict range activities, you may have cause for damages.