What kind of window are they spraying it over the top of?

I would have some concerns as to the ability to have it release in the seams and depending on the porosity of the material.

It's on the interior, wood. The research I've done shows many use it when there are multiple mullions to easily mask off areas. It doubles as a primer so when you're done you cut away and peal it off the glass. But like I said I have no real experience or first hand knowledge of this product working or how effective it is.