Regarding using this technique in an ASP environment, I would perform some additional testing.  I'm not sure how Context_info applies when using connection pooling, but either way would appear to have problems.

• This may destroy the ability to use connection pooling.  Then each user will have there own connections, increasing resources on the both the db server and web (or app) server.  Scalability and performance of your site will likely decrease.
• Or, if connection pooling still works when using context_info, then you will run the risk of having the Context_info reset on the connection, or being used by the wrong user.  In an ASP app, there is no guarantee that you will get the same connection each time.  And, other users will share the same connection.

Even still, thanks for the article, Yousef.  Especially for the first intended purpose, this appears to the an elegant solution to your problem of restricting updates.