I suppose the easiest solution would to be insert the Ad(s) inside an object, like:
Code:
<div id='AdObject'>ADS GO HERE</div>
Then use a little bit of javascript to detect if the ad is there or not .. and then if not, js will redirect them to a page saying bla bla bla.
What types of ad's are you using, if i can look at them i can show you how to implement this method.
- Zero Tolerance