Non--board-game people keep making up their own rules, without knowing it.
I'm talking about players who are intelligent and literate, but who don't generally play board games.
Is there anything a game designer can do to help them understand how the game is played?
Examples of the Problem
In one game, you move your piece around the board. The rules say you may move your piece up to three steps. There's a pair of dice included in the game for a completely different purpose. This kind of player grabs the dice, rolls them, then moves their token that many spaces.
In another game, there are many different cards. Each card has text on it, saying what it does. This kind of player plays the card and does something completely different than what it says. For example, if it says "When you play this, you must discard all your cards and gain $10.", they might play it and take $10 without discarding anything.
Or, this kind of player looks at a card and announces that they don't understand what it does. But when you ask them what it says on the card, they read it, then say, "Oh, that's what it does.". (Note that I'm not talking about players with low literacy skills.)
Why I Care
I'm a board game designer, involved with the publishing company, so if the rules aren't clear enough, I'm the one at fault. The good news is that, if there's any fix to be done, I'm in a position to do it.