I changed accidentally the value of a BusinessObject-property that implements INotifyPropertyChanged from within a BackgroundWorker (BackgroundWorker.DoWork).
Amazingly, this led not to an error but actualized the text of the TextBlock that was bound to the property without any complaint.
Is the execution of asynchronous bindings part of the WPF binding engine or is this only a special case where the CheckAccess-test have been forgotten or ommited due to other considerations.
Bindings on scalar properties support updates from other threads, so you don't need to call Dispatcher.Invoke when updating a property of the model (or ViewModel). However, this is not true for binding to a collection: if you have a ItemsControl bound to an ObservableCollection<T>, changes to this collection must be done on the UI thread, as CollectionChanged events are not automatically forwarded to the UI thread. Alternatively, you could use a variant of ObservableCollection<T> that raises the event on the UI thread (here's a implementation)