When miner encountering a fork, one fork has less difficulty but longer in length, while the other fork is more difficult but short. Which fork should miners choose 
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?You know, the miner should choose to mine the longest chain that the network is likely to accept. Because mining a short chain will be pointless, because the network will eventually abandon that chain as well as I know and understand the point you are making.
And accidental hard fork are also relatively rare and resolved quickly as well too.