Allowing bots (Google, Yahoo) through restricted forums

[boyscout]

Technically, this wouldnt be cloaking, nor would it affect adsense. Adsense banners are only clicked on by a physical user, therefore that user would need to be registered. Secondly, it wouldnt be seen as cloaking either, as a visitor viewing the site, will still have access once they register and will be able to see the searched for information.

I also realise i need to do checks on the useragent, but have no idea where in Vbulletin I would do this. Any help would be much appreciated.