New etiquette rules with Twitter?

With many discussions about the various impact that social networking services have on an organization and individual, IT pro Rick Vanover raises some questions on basic protocol.

I am a selective fan of social networking. Primarily, I use Twitter to communicate many blog posts and follow various technology and news topics. After reading through many discussions about social networking on TechRepublic forums, I thought it time to raise one question about new etiquette that may be in order with Twitter in particular.

No Tweeting, please!

Is it okay to ask people not to Tweet? I think so. Just like you inform people that photographs are not permitted, an organization (or individual) should be able to request this courtesy. Enforcement is impossible, but the same goes for photographs.

Unbeknownst Twitter activity can be risky for many reasons. This can be everything from catching a slip of information or conveying misinterpreted facts or clearly false facts.

A good example of this is where a technical colleague of mine had attended a nondisclosure, in-depth technical session on next-generation servers from a major brand. Many details of the event were sent out via Twitter, likely in direct violation of the nondisclosure agreement. While most nondisclosure agreements are written to accommodate anything, social networking and Twitter are generally not spelled out specifically.

I feel it's totally in line to request someone not to tweet information for a particular subject. It still is impossible to enforce and very difficult to determine if someone ignored the request. What is your opinion on an etiquette practice such as this?