I thought it would handle it a bit better as well. So what I did for my test is serialized my object and then extended my class by adding a readonly property. I then tried to deserialize the object and get the following error:

Error in line 1 position 132. 'Element' 'iNumber' from namespace 'http://schemas.datacontract.org/2004/07/TestApp' is not expected. Expecting element 'bNewProperty'.