Using County Assessor data

I was looking at the local county assessor site, and I started to wonder if I could use their information in OpenStreetMap.

There seems to be two conflicting opinions: http://wiki.openstreetmap.org/wiki/Parcel (says you can) http://comments.gmane.org/gmane.comp.gis.openstreetmap.region.us/5504 (one of the posts says you can't). And then the county website: http://www.mesacounty.us/template.aspx?id=45

The county has a (blanket) copyright notice for their information, and as far as I can tell, the state of Colorado has no laws affected copyright status either way. I'll keep on using general knowledge of my area and places that I go to for now though.

----EDIT----

Ok, I did some more searching, and found their data download portion: http://gis.mesacounty.us/datamap.aspx

Extract:

    Mesa County currently distributes a GIS data set as a service to the public.  The County provides this service to promote the sharing of data among all governmental agency and private GIS users in an effort to reduce overall cost of data collection.  In return Mesa County requests that all users of the Countys data set provide non-propriety data which are created, collected or modified to the County for internal use as well as distribution to our GIS user community.

This seems to indicate that it can be used, so long as Mesa County can use it as well. I don't know if this means the CC-BY-SA is acceptable for that purpose.