That seems to be a sensible behaviour, but it may not suit everyone. As it is, Wish is just a simple flag that could be used in a number of ways. It may mean "wish to buy," regardless of what's on the HDD. Or "wish to view in theatre," regardless of any owned media. And if a DVD is purchased, most would want to turn the flag off, whether or not the DVD is scanned or ripped to HDD. Those who don't want to maintain a wish list might use it for something completely different. Also, there is already a filter based on the existence of a File path, so it's not clear it's necessary for Wish to behave as it's compliment.
Removing the wish flag automatically would be useful and increase accuracy for many, it would have to be optional.
