Copyrights are important only if someone intends on defending them. I don't see anyone here suing anyone even if the deck is ripped off. Why would anyone need to give the organisers permission to manipulate the image, anyway? Is that really necessary? Isn't it implied? If the printers print the deck, yes, that could be considered a problem in certain cases. But copyright is civil law, meaning you go after it yourself. Will anyone sue the printers for doing exactly what they want them to do? It is a breach of copyright only if someone decides to defend their intellectual rights. But here there are no rights and if there are, they don't matter. Plus, I think it is an overly ambitious proposition, the idea of allowing others to use the work from the deck. That would be important if the deck were high profile and made for publicity. It isn't either of those things.
If you don't want to defend your artworks in court, then that is freely your choice to make. No one will force you into it. But you're responsible for decisions about your artworks, including how you'll use them for this project.
Basically the one responsible for protecting your artwork is you. No one will care if you don't.
If the organizers don't see it important to inform the artist that they will change/manipulate the artwork, then they don't need to include it. But it's dangerous to think that it will be implied, and it's better to make things clear so everyone is well informed.
The idea of allowing others to use the work from the deck freely, is what the organizer wanted, and so I took the time to find out about many different licenses, and the CC BY 4.0 seems like what the organizer wanted. It allows others to use the artwork as freely as possible, while crediting the artist in return. The artist still retains personal copyright ownership of their work, but is just giving permission for others to do creative things with their work as well. But you don't have use the license if you don't want to. The license is optional.
And lets not forget who ever sues a person that has infringed on copyrights will actually cost you MONEY!!! even if you knew that person/persons was who had stolen your art work? you are going to need to pay for a solicitor/layer to help you send a letter of warning which i might add is not going to be cheap?
The automatic copyright doesn't cost a dime to you. It is up to you if you'd wish to pursue the matter in court. You could always send a message to that person to take down the artwork, or else further legal actions will take place.
Although "registering" for copyright does cost money, it also provides evidence in the court of law. Basically what registering for a copyright does, is create an official record of when your artwork was made, and also states that you're the owner.
Hiring a lawyer also costs money, since they charge rates and fees for the service they're providing you.
But let me remind you, all this legal stuff, whether to pursue your stolen artwork or not, is all up to you. If you wish to pursue it, go ahead. If you don't, that's fine too. The main thing is, it's a choice that's there for you. I don't think anyone will push you into spending all that money in court, nor hiring a lawyer if you don't want to.
The important thing is, it's your artwork. If you don't want to chase criminals, then don't do it. But that doesn't mean that the artwork isn't yours. So you choose what you want to do with it.
But since the organizer doesn't want to deal with all these things about court and pricey lawyers as well, she wanted this deck as free as possible for everyone, to print and redistribute, to change, and even to sell commercially if they wanted to, to avoid disputes about pirating as much as possible. I'm trying to offer a solution for these needs. I understand that I don't need to keep going on and on about copyrights this and copyrights that, but those things about printing and pirating will otherwise become an issue forever. I'm just offering my help, although I understand it doesn't always seem that way.