Unfortunate situation there. Can't say I have been in it. Razor blade scraper is the first thing I would reach for. Long reach ones are available for areas like over the dash. Whether removing the windshield would be prudent depends on several factors which I'm sure you've weighed in your head. That sucks pretty hard that someone spray tinted a windshield, though. Wow!Thanks, but, that's for film applied to the windows. The tint on my windows was sprayed on like paint.
Maybe try gently using some clean 000 or 0000 steel wool under the thinner rag.I tried the following with no success:
MEK
Perchlorethylene
Brake cleaner
Lacquer thinner
Denatured alcohol
Mineral spirits
I did have some success with the lacquer thinner and a lot of effort.