Tom is right. And we loved the Rules engine that we had in place to deal with incompatible types. It caught lots of nasty things that would go unnoticed and lower our data quality in Freebase.
As I said before in another thread, Wikidata needs some sort of Rules engine to deal with the cross domain issues or incompatible statements during merges, etc, as Ben is experiencing.
Thad +ThadGuidry https://www.google.com/+ThadGuidry