Great idea Sparrowhawk (even if you didn't know you were suggesting that forum to us individually, I liked the spark it lit. Nice execution Megiddo)
As for the code, you did better than most to find where the button code is.
Want to try to learn/tinker with lua? Let me give some hints.
Just install ULib/ULX on your client game, play singleplayer. No harm done to server that way.
local button = vgui.Create( "DButton", window )
button:SetText( "Close" )
button.DoClick = function() window:Close() end
button:SetSize( 100, 40 )
button:SetPos( (window:GetWide() - button:GetWide()) / 2, window:GetTall() - button:GetTall() - 10 )
You would need to duplicate that, changing the second portion of code to local variable button2 (just to keep the name easy)
Set text is obvious. Change original button variable portion "Close" to "I disagree", and button2 block code to "I accept")
button2:DoClick ... hmm, that is where I would have to tinker myself (and don't have time really right now.
try
function() window:Close(); Msg("*** You didn't follow directions in the MOTD ***"); RunConsoleCommand("disconnect"); end
Leave size the same
button:SetPos and button2:SetPos - Figure out the math to do thirds for the buttons along bottom. I look at the math in that and remember my typing classes (yes, pre 'keyboarding' in school) and can see its similiar to centering currently. 1/3rd for button and 2/3rds for button2.
Have fun learning