Do ask permission before you take photographs of people. A lot of Pagans are in the broom closet, meaning that their bosses, parents or some friends may not know about their religious beliefs. They would be very pissed if a picture of them wearing a pentacle and robes and dancing around a bonfire showed up on your website for all to see. Some gathering sites will not allow you to bring a camera on premises. Be sure to ask the coordinators about this when you arrive.
Some people use the energetic environment of a gathering to cleanse and charge their tools.
They may not want you interfering with the energies by touching their stuff. If you're at a merchant stand, it's usually fine to handle the merchandise, but if you see a tent with a blanket outside covered in magickal tools, please ask before you try to touch anything. Do not assume that just because somebody is naked that they want you to hit on them. That doesn't mean they want you pawing and drooling all over them. It's OK to look, just don't be grabby.