Understand tint beyond a certain point is illegal in AZ.

Last car I had tinted was great, but I had darker when I was a kid (early 90s).  Much darker.

Question is, is it illegal to APPLY, possess on the glass, or both?  As in, can the shop get in trouble, or just the vehicle owner?

I think it’s on the vehicle owner. Every shop I’ve been to in the last 20 years has offered limo tint up front and windshield tinting. But that is not a legal opinion.

I know a few guys who’ve had their windshield tinted at 50% and they have never had an issue. I’ve run full limo tint (sides and back) and nobody cared but it was way too dark for me. I sold the car to a neighbor and he still has it 10 years later and no issues.

Our tinter at work will put whatever you want, on any window you want. He flat out doesn't give a shit about the laws.

But, that would change if he knew he could be held liable for any tickets someone got.

I've had limo tint on the sides and back of my 08 Chevy truck since we got it new.
Been pulled over a lot.
Never received a tint violation or even had it mentioned.

Just when vehicle is driving down the road. Shop can apply anything, it’s you that will get a ticket…. If cop even decides to do it. Mostly DPS. City cops have better things to do.

I've got a black on black Challenger, and I've got limo on top of the tint that's already in the windows. It's very obvious, nobody cares. I've been right next to cops so many times and they've never even looked twice. Had it that way for 7 years. Shop I go to doesn't care, they even give you the full warranty they just lie on the receipt. Already had to have it redone once a couple years ago

What you want is a good ceramic tint ,work's better for heat and much more optically clear. You don't need to go too dark to get good tint protection and your radar detector will work better with ceramic tint than cheap metalized tint . Check out Cools window tinting 1 north 35th ave ,3M ceramic tint. the place doesn't look like much , but they do a great job at a great price.
Metalized Window Tint (Better) – Reflects heat using metallic particles in the film. ... Ceramic Window Tint (Best) – The best results from a window film. Ceramic films use ceramic particles to reject heat, sun glare, and UV rays. This film offers the highest levels of all categories while never sacrificing visibility.
So it's a matter of choice ,go too dark  for so called aesthetics , or get the best product for  ,viability and performance.

I have tint on my windshield, it’s 93% so it’s barely noticeable but it really keeps the heat off the dash.

If a cop is on a fishing expedition, this is one thing that will trigger them.  I had limo tint for 12 years and was stopped 4 times.  I got the ticket on the 4th time.

If you have one beer at a bar and leave around 11-12PM, you have to ask yourself, would you rather have a "stop me" bumper sticker, or limo tint?  

PCSD used to have a tintometer in some of their cars. Some of their cars had illegal tint in them.  Some agencies simply don't care.  CHP enforces it heavily, but I doubt they care much about it with AZ plates.  It can still earn you a conversation.

If your are going to be driving at night ,you will find the Ceramic tint to be far superior and more optically clear with less glare and better resolution .
So you can get the best tint benefits and  results with a ceramic tint that is not too dark to hinder your vision or function/ range of your radar detector  and still be legal here and in California.