There is also an issue with people listed as "No Family Tree". That could either mean they really don't have one, or it could be they have public trees but just haven't linked it to the DNA tester. If you click if will show their public trees, and if they only have one I assume they are in it and select that. However, you don't know for sure if the "home" person for the tree is the DNA tester because the DNA tester's entry in the tree will be private since they are (presumably) living. If they have multiple trees, you can check each one to see if any appears to be more likely to be a match (locations, names, etc.). I'm not sure if there is an answer to this one, other than to ask them nicely to link their tree.