I'll offer some advice which might help you not being caught. Bring a friend or several to the Beach and have them pose in front of your real target, which might be 30-50 yards away. You will of course be a pest and have your friends (who should be in on the idea) take up a variety of positions, all the while you are really focusing on the babes further ahead. Hardly anybody will take any notice of your activities (as even girls take a lot of Photos of their friends) - unless some specialist will wonder why you are using lenses on someone who's right in front of you
