VDJ is a internet friendly DJ program and being on the internet while DJ'ing should not cause a problems. I have now done two event casts and I have had no glitches. Here in ontario I have not been in a venue that does not have internet access.
For those venues where you do have a great connection and there are no errors, it may be nice. What about the times you do have an error? You have to have a plan in place for that - because if you don't, using the technology that broke will leave you left behind.
Totally understand about a program being Internet friendly - but if there's no Internet, what's it friendly to?
I have been in plenty of venues that either don't have Internet access or charge a fairly high amount to use it - and as recently as this past spring have used plenty of venues free Internet (cabled and wifi) that was extremely horrible at best - and these were nice, popular locations. Bringing along your own wifi may be problematic as well.
Example: The metro DC area more than likely has high speed in most places. 60 miles away and more (in the woods), several do not. Depending on the venue, you may have to pay (quite a bit) for that access. Regardless of how fast that connection is, it's only good as long as the link is up - and they do go down. Even if the actual link doesn't go down, paths can be lost.
There's nothing wrong with using technology in the best manner possible. There is something wrong with being dependent on a technology that is not robust enough - and not in enough areas. I've seen places where you have a connection .. but the Internet is so slow that it would be quicker for you to walk to the server. I've also seen 'timed' connections.
My point being - all that technology means crap when you can't get on the Internet or can't use it.