That would be a good idea, but I am not sure if it would work. Afterall, most of the people that break the rules are those that wouldn't even be bothered to read them if they could(read: lazy people/punks/idiots).
Here's an idea that I'm not sure is possible, but may save headaches. Make a forum called Read First. In there include the rules of posting where you explain where to put download requests and such. The reason I suggest this is the rules of the individual forums kinda get lost to the eyes in the list (despite being stickied at the begining).
Could you please explain further? Are you saying that the password is hidden in the list of rules, or that you have to read the rules before you can continue with registration and getting a password(such as when some software makes you scroll through the license before you can continue with installation), or are you saying that you need to be quizzed on the rules before you can recieve your password? If the first one, I don't think it would be a good idea, even if you are allowed to change your password later. Having the same password for everyone in the beginning would probably mean that many people would be taken advantage of, and their names used to abuse the forum. If you are talking about the other two things I mentioned, I agree, that is a good idea.
Or, make a password necessary to enter forums that you can only get when you read the rules. THis way those that jump in without reading the rules will have difficulty posting without knowledge of the rules.
Just some ideas.