Yes definitely. Really no different than if you would want someone to
enter your house to close your windows.
Now you might say "well what if it can be done from the outside" without entering?
That is a bit different.
Except for one thing. What if someone saw you doing that? What if the owner saw you doing that and didn't know why you were messing with their car? (I had this happen with a boat one time btw.). There is an immediately sense of shock because you don't know what is going on. And in that case who knows what will happen? Maybe they might start a fight or shoot you. That's not good for anyone. Maybe they have something valuable in the car that they think you are going after. Maybe they have serious mental problems.
Here's the point. It's one thing if you see a baby in a hot car and decide to take action. The benefit outweighs the risks. But it's another thing if you decide to roll up the windows to prevent someone's car from getting wet inside (covered by homeowners insurance with low deductible in many cases ntim though). Different story. Make sense?