It depends on a number of factors such as wind that day, how much moisture is in the air, is it a zoom lens that expands, are you changing lenses (I wouldn't change mine). A general guide I would follow:
- If you are using a zoom lens that expands I would wrap a plastic bag around your equipment if it were a windy day. The last thing you want is some sand landing on the barrel then ending up inside the camera. Or use a fixed focal length lense. AS your using it, watch for anything that might have landed on the barrel before zoomingin and out. Generally keep it off the ground, and sand probably isn't "flying around" unless it's really windy or getting kicked up. Most often you probably don't need a bag if your careful and not laying your camera down near the sand.
- If sand does attach to the camera or lens, and if it sticks from the moisture, wait until it dries and gently blow it off with a blower (DON't wipe it off the front of the lens).
- If you have a good quality clear protection filter (multi-coated) this is a good situation to use it.
I wouldn't stay away, but just be aware of the elmements (sand) and be mindful and careful. Then use care when cleaning after being on the beach.