I have been hearing the "I had no idea that was against the rules." excuse quite frequently. Many even type !motd after their told its a rule... Perhaps we need a more, binding rule page. I remember one page for a darkrp server I once played on, basically, it had a checkbox for the "I agree", mentioned "ignorance is no excuse", and would popup again for everyone after the server crashed or was restarted/new day. I feel this may be needed so people can't just play it off as if not knowing the rules isn't a big deal.
I don't understand why you continue to make posts about players not knowing the rules. If players don't know the rules then they're going to get slain, and by getting slain they're going to learn pretty fast what is considered RDM and what is not. I don't see any benefit to adding a check box saying "I agree to the rules" before you can enter the game. By playing on seriousttt, you are automatically assumed the position that you've read the rules and regulations, and will abide by them. If players fail to comply with the rules, then they will be punished, there is nothing more to say. There will always be players who join the server without having read through the rules, and there is no amount of text or check boxes we can add to make them read the rules, that's just the way things are. Players who want to play their rounds and not sit out slays will read the rules fully and ask questions if they're not sure about something. There are players who will be punished for not being competent enough to read and understand rules, and their will players who enjoy their experience playing the game because they have read the rules.
Our server rules show up for every map change and when you log into one of our servers. We, the staff, even give messages for people to access and read the motd. By playing on our server, the players acknowledge the fact that they understand and will abide by our server rules. We shouldn't have to put up a "legal" binding agreement, since it is not one. Players that break the rules, quickly learn to type "!motd" and pay a little more attention to them.
Your right, I totally forgot the rules show up each time... Perhaps change the color scheme a bit to something more, brighter? I truthfully forgot the page shows up constantly. (Though I know the rules quite well.) Mainly because of the colors...there so... forgettable. Brighter colors might encourage more attention.