Comment 9 for bug 328606

Checking capabilities requires a round trip on DBus. Which could be delayed by the notification daemon being busy. It definitely will be if everyone check capabilities all the time. For the number of times that people change notification daemons, I think it's better to check once.

The correct way to implement it would be to attach the name owner and then handle the case where the name owner is destroyed as it drops off the bus. But, those patches would get rather large. Again, I think this is a pretty minor usecase.