What is the purpose of allowing IndexedDatabaseRequest ( http://dev.w3.org/2006/webapi/WebSimpleDB/#idl-def-IndexedDatabaseRequest) to raise an exception? The only mention of it in the spec is that it raises a NON_TRANSIENT_ERR "if the name parameter is not valid". But it's not mentioned in http://dev.w3.org/2006/webapi/WebSimpleDB/#dfn-steps-for-opening-a-database or anywhere else as far as I can tell.
I don't see any reason to special case this one method with synchronous properties. "If the name parameter is not valid" or any other error, I think it should be returned via an error callback just like everywhere else. J