INETA conference and a disabled network card => big GOTCHA

Hi again, last March 26th I flew to Saskatoon to give the first conference of two for the INETA Launch. This event is part of the Microsoft Ready to Launch Tour. I had splitted the content in two conferences, one for developing the web application and the other one for the smart client and a bit of the data platform.
As you can imagine I was pretty nervous on this first conference. The first three demos worked fine but the one regarding Data Access failed, I was 10 minutes over the scheduled time and apologized to the audience telling them i would look into what had happened.
ASP.NET 2.0 makes the data binding quite easy, no need to write a line of code to pull out data from your sql server. Unfortunately, the easiest demo failed.
When I tried to reproduce the demo at the airport it failed again, it only worked once I was at home and had recovered from the 2 hours of sleep from the day before...
What the heck happened then? I'm a technician and certainly don't believe in magic... I searched for user permissions, thinking perhaps the user I had used had no permissions in the database, I studied deeper ADO.NET 2.0, googled about the problem, read the reference to the point of exhaustion et-cetera.
Anyways, on my trip to Cuba this weekend I commented this issue to one of my ex-coworkers as he asked about the conference. He said, did you have both your Wi-Fi and your Ethernet card dead? I said, yes, I was completely offline when I was giving the conference...He said, well, you had no TCP/IP enabled and you certainly didn't have the SQL Server Personal Edition, or configured your server to use something else...
OH NO! Whatta a gotcha! Damned!
He said, even if you put a network cable, as long as your network card sends packets, it should work...
Ok, I hope I'm able to make the trick this May 6th on the second conference, something like, now it works, now it doesnt, with my network cable on one hand ;) , it'll be fun...