and dont reply with the fake rhetoric of split coins, which can only occur by blacklisting nodes to by pass the orphan mechanism
Actually, it could occur in multiple situations.
One would be a bilateral fork, where the fork intends to ensure the viability of all networks. For example, blacklisting blockchains that do not contain the fork block, or otherwise changing some consensus-critical factor to ensure a split. This is beyond the scope of "longest chain".
Another would be something like the DAO fork. ETH had nearly 100% of the hash rate at some point. But since the original network will always reject the hard fork blockchain, anyone can return to mining the old chain at any time, and there will be a network split.
You would only know after the fact if there was "consensus" in a hard fork. If there was not, users remain on the original chain....and miners will come.