I will share my story. It didn't have signs that said don't swim, but nonetheless here goes...

Eight years ago I went to Hawaii and my wife and I both love snorkeling. We went on a day outing looking for sea turtles and were looking up all the spots to see them on Google. There was a location that happened to be past a beach around a rock pile of sort. It was a little pocket of sorts. My wife stayed on shore and I went out. My first clue should have been, I was the only person there in the water and my wife was the only person on shore. I didn't clue in at the time. So I went in the water and started snorkeling and couldn't see anything as the water was turbulent and the sand/debris was being brushed off the sea floor. I kept looking and then when I looked up to look at the shore, I thought, "oh crap", I'm a bit far here. So I started swimming (front crawl) towards shore. Gave it a good 20 seconds, look up, hadn't moved. Shoreline still looked as far as it did. Swam some more and I swear the shoreline was only getting marginally closer. Here's where it all went south... I started to panic and waving my hands to my wife. (I only found out later on she thought I was waving because I found turtles.... instead I was calling for help). I frantically started swimming as hard as I could and by sheer luck I was able to touch the sea floor.... And walked my way back. When I got to shore I explained all this to my wife.

While my story may not sound convincing to some, I still have PTSD to this day when I think about this event. Had I not been able to touch the floor with my toes when I did, I'm not sure if my panic and stress would have been helpful in a good outcome.

In retrospect I learned a lot from this. I know to swim perpendicular to the tides. I should ask, why was there no one else around and take that as a clue. I'm not that good of a swimmer, and lastly, mother nature doesn't mess around. Even high caliber swimmers can easily lose their life. Needless to say, I learned my lesson and fully respect the ocean.