I too think that any film that is built to be marketed for product tie-ins is stunted (though a select few can pull through with their sheer fun) at conception.
If that were to happen, I agree, but I don't think product tie ins have any significant impact on a movie. That's a bit of a wag the dog situation. Maybe we see Lara Croft use a Nokia mobile - so what?
I don't think that because a given movie may have tie-ins with Pepsi, Burger King, Hasbro, or whoever it means there was any influence on the final product. There are BK promos for LOTR, but I doubt PJ ever gave that a consideration during any aspect of the production of his movie.
Mark