I no not think an erection is anything to be ashamed of. But, if it happens, you should not draw attention to it and try to be discreet in family nude venues. If all adults, just go with the flow and don’t flaunt it.
The many times we've been to Haulover Beach we've never seen a full blown hardon, but many semi erections. There's a rather well known black guy that's always there who's rather proud of his and always chats me up. Once as we stood there conversing, he started getting semi erect. As hard as I tried to keep my eyes focused elsewhere I kept glancing down at it. He noticed of course and ask me if I wanted a picture. lol
I've seen erections encouraged once on a Croatian beach. Three nude young ladies on a cramped rock platform were laid parallel and kept oiling, getting on all fours and rotating in front of a chap who's cock was straining all afternoon. No one seemed perturbed in the proximity,