So basically, if I understand correctly, this is a hack that favours the miners.
And obviously, miners would be motivated to make a fork happen.
Am I correct?
What do you mean "hack"? If you are talking about the guide - it's a necessary thing to do for everyone who wants to save as much money as possible. If you are talking about the trick of creation of exclusive coin inputs - yes, it favours the miners because gives them a way to sell 1 BTC for 1000+ BTC.
Well, since I doubt anyone will be selling these newly generated coins or be lucky enough to get his transaction in only one chain,
it is logical to assume that we will see a lot of this hack (or trick if you prefer) happening by miners.
The question is: Where does that leave the average Bitcoiner who is not aware of it or lucky enough to get them coins and attempt to double them?