Hejsan

I have had the same problem. It is usually solvable by not accepting the rules they offer, and just keep nagging until they don't ask you to blend rules. However, from my experience, the further in the game you get, the harder this gets to keep up, so I mostly end up giving up and accepting the random rule in the end.

If you're not keen on getting a complete collection of cards, you could refine the cards you don't want to use, and the random rule won't do that much damage. I like to get all cards in my collection though, so I don't do that.