Sony's PS3 net service has a big EULA that you have to read before you can join. I scrolled to the bottom as quickly as possible and continued.
All this would accomplish is being able to say "well you were SUPPOSED to read those rules; ignorance is no excuse!" when someone broke them, and isn't that generally true, anyway? The people who are already responsible netizens will either look for rules on purpose or intuit them based on the rules they follow elsewhere. The people who are going to be a pain in the rear are going to do it regardless of whether you tell them to read the forum rules.
I think a better solution would be to make links to the rules more prominent: visible on every page, linked with a reminder during the sign-up process... sure, maybe even inserted into the sign-up process as something you "have to" read in order to post. It's not going to prevent anything, but it would make it easier for the well-meaning posters to figure out what they did wrong when someone slaps them around for breaking a rule.