Mobile Safari 5.0.2 for the iPad (DiigoBrowser Mozilla/5.0 (iPad; U; CPU OS 5_0 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5) is not correctly detected as a tablet device, as can be seen here:
http://www.tera-wurfl.com/explore/index.php?ua=DiigoBrowser+Mozilla%2F5.0+%28iPad%3B+U%3B+CPU+OS+5_0+like+Mac+OS+X%3B+en-us%29+AppleWebKit%2F533.17.9+%28KHTML%2C+like+Gecko%29+Version%2F5.0.2+Mobile%2F8J2+Safari%2F6533.18.5&search=Lookup+User+Agent
We're on .NET API v1.4 RC1 using the database from Mar 18, 2012.