I haven't found anything with my searching, but then I'm not quite sure what to search for. So if this has been covered I apologize.
I'm considering having a button for a new user to have to push before s/he can post the first time. Said button would read something like "I've read the guidelines and accept them as a requirement to be able to post in this forum." Is something like this possible?
This should be possible, but definitely is not one for the faint-hearted! Hence my suggestions for alternatives...
It would be a lot easier to add the text of the guidelines to the registration screens, but presumably you are thinking of users who may have registered a while ago and have only just thought about posting?
Another "work around" would be just to insert a line on the message edit page with a link to the guidelines page although, I accept, less intrusive and very easy to ignore.
In my view, there's not much point in your proposed button unless the "Post" button is disabled until the new button has been clicked, but that strikes me as a bit of a waste of time if you're not going to send to, or at least provide a link to, the page with the guidelines on it. The question you need to answer is - will pressing two buttons rather than one to make a first post really help ensure that your guidelines are followed?
Why am I so keen on dissuading you from your plan? Bear in mind that to achieve what you want, no matter how simple the action, you will need to provide code that executes that action when the button is pressed and that code will need to record whether the currently logged in user has posted before, regardless of device (so it can't be done by planting a cookie on the user's machine).
Effectively, that means you need to create another user group along with "Anyone" and "Registered" to which people are assigned automatically once they click the new button and I haven't begun to think whether you'll then need to add code to manage that class should something go wrong. (I have no idea how to go about any of this!)
My own feeling is that any guidelines page should be extremely short to the point of non-existence and that the best route to appropriate posting is to have sub-forums constructed logically so navigation for new users appears straight forward and that sub-forum descriptions make clear the what are appropriate topics and include links to related areas that may be more appropriate.
Just a Volunteer Nabble Helper - because the nice folk at Nabble have helped me! GregHelp - Building a set of answers to Nabble FAQs.
If you're not faint of heart, search for the registration_fields macro, add another checkbox like the one Nabble does and make it require it be checked for submission. Post a link next to it for whatever you want them to accept.
I'm not sure how to do make it require it to be checked offhand, but one of us might figure it out eventually.
Mine won't let me edit that macro, though, without causing an error (even if I don't make any changes).