WordPress MU

I read somewhere a Wp blogger stating that WpMu is a great script but I some know how to make money out of it please let him knows. Would it be a good idea to place a adsense code in every user templates header.php and footer.php whenever the template design allows, and intead of adding adsense plugins to place ads automaticaly do it manually in each template so this way user cannot modifie. since the blogs sercices are free for them?
I know that modify each template would take a while, but, is it whorty?
Please drop your opinion.

yes wpmu is a great platform for that.

Users can't edit templates in admin.

Let me correct my post, Coz yesterday I posted it over the phone

I read somewhere a Wp blogger stating that WpMu is a great script but "he" would like to know how to make money out of it. If someone does please let him knows.
So I think.
Would it be a good idea to place a adsense code in every user templates header.php and footer.php whenever the template design allows, and instead of adding adsense plugins to place ads automaticaly do it manually in each template so this way user cannot modifie. since the blogs services are free for them?
I know that modify each template would take a while, but, is it whorty?
Please drop your opinion.