How does a script fallback gracefully when Google Gears access is denied by user?

Question

This is a two part question, if I may.

First, I need to find a way to make my script to fallback gracefully when a user denies access to Google Gears. This is the way I do it now:

    try {
        var workerPool = google.gears.factory.create('beta.workerpool');
    } catch (e) {
        this.gears_forbidden = true;
        return;
        // User has denied access
    }

But maybe there is a better way?

And the second part - After denying my development page access to Google Gears once, it stopped asking for permission. Although this is understandable, maybe there is a way to reset my preferences and make this dialogue appear again?