On a relatively recent discussion, one citizen complained that there is no 'binding agreement' or contract between citizens and the CDS. Some have shrugged it away as being not relevant, but I think it is. And I thought, in fact, that long ago we actually had contracts.
Now, by mere chance, I found a way to fix the historical site for Neufreistadt at http://neufreistadt.info/ Back in 2006, every time a citizen bought a parcel, they would have to agree to a Deed. Here is the text for it:
http://neufreistadt.info/id27.html
This is a template, of course, every Deed would be written out for a specific citizen and a particular parcel.
But the Deed was not all. Participation in the CDS assumed the agreement with the CDS' Terms of Service. Here they are: http://neufreistadt.info/id28.html This is actually a slightly more recent version; the original (which I have lost) had "Neufreistadt" instead of "CDS". You can tell because here and there the word "City" is still present in that ToS, which had not been corrected since 2006.
I have no idea if this document still has legal value or not. My point is that we did, in fact, remember back then to make participation in the CDS adopt the form of a legally binding service agreement.