Skype network crash - could it have been a DOS attack?

At BlackHat Europe, March 2nd and 3rd, 2006 (PDF here) and then at Recon, June 17th, 2006, Fabrice DESCLAUX and Kostya KORTCHINSKY gave a rather detailed analysis (in two pdfs, part 2 here) of how Skype obfuscates what they are doing. 

One of their conclusions that really struck me at the time was this bullet:

Fully trusts anyone who speaks Skype

As is made clear in their analysis, Denial of Service attacks are possible.  I wonder...