This isn't really necessary to notify, as most games provided online will most likely get pirated one way or another. Sure, it's a bit shitty when it happens with games that are very inexpensive, but more often than not, it leads to more users finding it and supporting it. Jumping through hoops to prevent it will only bother actual supporters, I find. Not like I'm an expert, just that in my experience, it isn't a battle worth fighting. People that want to support the game, will do so, and those that won't/can't, won't. It's not like anything changes in that regard.
The nature of the skimmer that has pirated the content is a simple patreon skimmer, the problem can be solved by simply linking the Patreon page directly to the Itch page, making everyone have to just log into the patreon account from itch. The bot cannot get around this, although the risk of other piracy platforms remains
So, a plaster fix? If we ignore the fact that it only really hinders a single avenue, how would that affect people that don't have/want a Patreon account, or primarily buy the game straight through Itch? It risks losing supporters, and you lose out on Itch's open revenue sharing model (Patreon takes at least 10% + currency conversion and tax, if I remember right).
If I were to be honest, this'll probably make the game basically dead and unable to play for people who just want to play the game without supporting it. If they want to play the game without supporting, just let them be. Some people just want to enjoy the game without having the pain to make a Patreon account and paying for membership just to gain access to the whole game.