Hi Nick. Yes, there is a no trespassing sign, at least, on the Fishing Cove Road side. No, it is not a new sign. It was there when I surveyed it a year ago, and it was there a half hour ago when I went to check.

Here is the photo I took of it:
https://commons.wikimedia.org/wiki/File:No_trespassing_sign_lit_with_headlights.jpg

It was late in the day, so I apologize for the lighting. It is geo-tagged so you can see the exact location.

Given how prominent this sign is, I'm surprised you didn't notice it in your survey.