SureAI

So I just got into this area without cheating. You can swim on the wolf mount out into the sea and climb into the area at the edge of the map. Worse still I can actually explore most of Silvergrove without getting this message and ask villagers about things which are probably relevant for future quests. Thought this would be helpfull.
I also found some areas where you can go out of bounds. In the last dungeon you explore with Esme(forgot the name of the area) you can climb onto mineshafts which lead out of bounds
.

It's always possible to get into areas like this somehow, as long as it can be found in the open world.
But all normal paths are blocked if you go in there too early.

For players who use e.g. glithes, bugusing and cheats there is this message, because you break quest with that. ^

The thing is you only get this message if you go near the gate, otherwise you can technically get in without knowing you have just broken the game. It's probably also possible to get in with a simple horse though I haven't tried that yet.