For those curious here is the function I ended up writing:
Function IsReferenced(sPageGUID, sLinkName)
sLinkGUID = GetLinkGUID(sPageGUID, sLinkName)
xmlData = "<IODATA sessionkey=""" & SessionKey & """><TREESEGMENT
action=""gototreereference"" guid=""" & sLinkGUID & """ type=""link"" /
></IODATA>"
xmlData = objIO.ServerExecuteXML(xmlData, sError)
objXMLDOM.LoadXML(xmlData)
If (xmlData = "<IODATA>" & vbCrLf & "</IODATA>") Then
IsNotReferenced = false
Else
IsNotReferenced = true
End If
End Function