I don't know anything about the law on this situation, but I experienced a funny situation in the Gulf of Mexico, many miles off Panama City.
Most of the published sites can get crowded on good summer days, to me is extremely annoying to transit 2 hours or more to encounter a boat on the site. So I used to go very early or very late. A captain of one of the boats at work gave me a dozen numbers that were supposed to be extremely exclusive, he knew well that I don't socialize with the diver community up there so the chances of me giving the numbers to others were zero.
One day my husband and I head out to one of those sites, and sure enough it would be our luck, there is a fishing boat on the spot. Well it isn't necessary to go all the way to the actual spot to see is occupied, as soon as we were certain that boat was on the spot we changed course and started aiming to another location. After we changed course the boat started moving, so we figured maybe they are leaving so we can dive there after all... oh noooo the guy was now pissy and coming at us very fast because he saw we have a radar dome on top of the cabin, and for sure we were stealing his numbers. There was a lot of red neck talk between the boats that I couldn't understand, but my husband is bilingual and working for the Navy all his life, can be as rich with his vocabulary as the nastiest sailor. Things didn't scalate further than heavy language and a few hand signals, but I got he feeling that we were close to move on to display of firepower... all for the numbers of a location that after I actually saw, I didn't think it was that amazing. But maybe because too many people had the numbers already and it was no longer as good as when the one first person found it.
the ocean may be huge but it has very big areas of nothing, google earth shows big wrecks along with published numbers but is the smaller spots that can produce a lot of pleasure or fish or both, but this smaller locations can't handle the pounding of boat after boat, day in and day out.
Maybe because I grew up among fishermen, to me is such a no brainer that spots in the ocean are closely guarded and should be respected. There's such a huge amount of published sites, leave the private locations private. It takes so much effort and resources to discover a good spot, making the numbers public is pretty much stealing. Yes we all have smart phones these days and it probably takes effort to actually disconnect the GPS but you don't have to write down the data collected, much less use it or give it to others without the blessing of the person that got you there.