Ran into this today: Opening an MEP model where the arch model had been updated. It threw an error that some dimensions were based on elements that no longer existed. I had to choose between not opening the model and deleting the dimensions.
Now I have an easter egg hunt to look for dimensions that are missing. It would be better to let you ignore or snooze the error. Another option would be to make the dimensions invalid...
The dialog box wouldn't let me "show" the offending dimensions, I had to delete them all to get into the model.