Yah it's pretty nasty. The great majority of these folks cutting up openspaces aren't even
hinting that there's anything different about their sims. There
was a recent discussion about this, and LL REALLY needs to put something in the UI to make it clear that there are different kinds of sims. Right now you have to really know what openspaces are and how to identify them by prim math.
EDIT: Two Jiras related to this problem:
http://jira.secondlife.com/browse/VWR-8768 and
http://jira.secondlife.com/browse/VWR-8770
Please vote!