People tend to do bad at a tournament if they just copy a list off of the internet without studying the deck themselves or doing fine tuning.
Even if we do something, we can't ever stop it. We have no right to say what someone else plays. Besides, even if you made a Dusknoir list, it could end up just like someone else's, even if you studied the deck and fine tuned it.
That said, I tend to not like it when someone copies an entire deck list and shows up at a tournament with it the next day. However, taking parts of lists that have proven to be good isn't that bad IMO. I say you need to add a personal touch to it at least.