Thanks for your comment, Kirby. I would define a secret sea glass beach as one that is really good for finding sea glass but other collectors don't know about. Some are afraid that if the word gets out, the beach will be overrun with sea glass fanatics scooping up the sea glass.
Some "secret" beaches are open to the public but and easy to get to. But most are a little out of the way. In either case, other seaglass collector's haven't found out that it is a great place to get sea glass, so is "secret" as far as good sea glass goes.