I think the problem is potentially serious for those many businesses who have switched to VOIP for communications.
It seems to me little better than a toy and I am surprised to hear that (serious) businesses use it. I don't even use it for voice calls, I find the quality unacceptable, and the saving on cost not worthwhile. Also I would not call clients using Skype as I think it looks unprofessional, like using a Hotmail or Yahoo email address.