Why not T&C as a node?

Yes, that's an approach worth considering. Got to way up the benefits versus the work involved to make the change.

I'm also cautious of using a node because at the moment I know exactly how the T&C data is used and where, if it's a node it becomes open to other uses: search, rss, views, tagging,... and I suspect it would show up in a lot of places where it's not really appropriate.

Before I even start thinking about that though I'll want to have complete test coverage. I've started work on that, but still more to do.

Just a thought

allowing PHP filtering could let one use nodes as "terms and conditions" content
http://drupal.org/node/265408

I know this is pretty old now but +1 for this.

You will often have nodes for privacy policy and terms and conditions anyway, which might be linked to in the footer or something, so it would be good if in this module you could select the page link display style and then just enter node id(s) for the page links.

As a side note, I can almost accomplish this just using the additional checkboxes to say something like:
I accept the <a href="/terms-and-conditions">Terms & Conditions</a> of use
and
I accept the <a href="/privacy-policy">Privacy Policy</a>

The only issue then is that the 'Terms & Conditions:' and 'Display Style:' settings are mandatory.

So just making those fields non-mandatory (if the user enters nothing and has no legal agreement let it be on them) would suffice, although it doesn't address the code duplication mentioned in the original post.

Also, see http://drupal.org/project/terms_of_use for a node based module.

I'm still against using the node system to store and manage terms & conditions.

The node system gives too much that is unnecessary and that can get in the way, I would have to add quite a bit of code just to remove stuff I don't want, and to enforce terms & conditions being un-deletable.

Will have a think about this again after the upgrade to Drupal 7.

Any news on this?

> The node system gives too much that is unnecessary and that can get in the way, I would have to add quite a bit of code just to remove stuff I don't want, and to enforce terms & conditions being un-deletable.

I think the above still applies.

Of course now that we're on D7, the T&Cs could be a separate entity type.

That would mean there'd be the benefit of having a body field (with input formats, wysiwyg support, etc), and the possibility of extension to allow multiple T&Cs (which has been requested various times).

Of course now that we're on D7, the T&Cs could be a separate entity type.

+1 for that. Actually, in terms of D7 we should ask ourselves "Why not T&C as an entity?".
Personally I would love to see some kind of "Static Entity type", which is intended to handle all of those special cases, such as Terms of Service, Home page, About & others: on the one hand they are nodes as they have body and revisions and on the other hand they need to be exportable by Features and shouldn't be searchable as a regular node.

http://drupal.org/project/entity_legal is another contender