Ask HN: Best way to Tweet on behalf of a user

I have a startup idea I'm working on which will make considerable use of Twitter. At the moment, I'm trying to figure out the best way to post Tweets from my web application on behalf of a user when they perform a specific action.

These are the options:

* When the user performs the action, the application will display the content that will be Tweeted, allowing the user to edit it. When they click the 'Tweet' button the form will post back to my server which will send the Tweet using the Twitter API. This method will require read and write permissions for the application.

* The other option is to popup a pre-filled tweet form on Twitter using Twitter's "intent" functionality.

The first one seems cleaner from a user interaction POV and has the advantage that my application knows exactly what was Tweeted, however it does require write permissions for the application.

So what do you folk think? Do you balk at authorising new, relatively unknown applications with read and write privileges on your Twitter account? Or do you feel that the ability to unauthorize an application if it misbehaves is enough?

Should an app offer clear assurances that it will be respectful of your Twitter account as part of the sign up process?