I’ve seen people use blankets that way.
It usually takes about 15 minutes for your car to start blowing warm air, in my experience. In other words, it starts blowing warm air just as you get where you’re going. 
About the parking spot in a crowded city issue - I think one possible solution would be for the scriptwriters to have the main character say “This is handicapped parking, but it’s an emergency so we just have to use it temporarily for now” - which would sidestep the “how could you find an empty spot” and also not have to show the character spending 5 minutes searching for a spot, which no audience wants to endure.
Ironically, the part that writers always get wrong is portraying authors.
They’re usually portrayed as being rich and successful; most authors don’t make enough to live on, and even successful ones only make enough to live comfortably.*
Also too many plots involved authors stealing a novel from someone else, something that never happens in real life (I know of only one case in the past 35 years).**
Finally, when they show a book manuscript, it’s about 150 pages. That’s not enough for a novel, where the minimum is twice that. Scriptwriters are used to seeing scripts and thinking novel manuscripts look the same.
Of course, these aren’t really a big deal, and they don’t ruin the movie. If anything, they make it more entertaining.
*Castle made an attempt early on, even showing him working on his next book, and with a screensaver that said “You should be writing.” But they gave that up after a handful of episodes.
**I’m not talking about taking nonfiction work and not properly attributing it – I mean actually publishing someone else’s novel under your name.
Mine is the usual - people knocking each other out with a punch to the head, and the puncher doesn’t break his hand and the punchee simply goes asleep for a few minutes and wakes up without puking.
Regards,
Shodan
Steganography. Admittedly the real thing is as thrilling as drying paint and would take the entire episode to explain in layman’s terms. It still isn’t zooming in on part of an image and reading the secret message on the screen.
There are several safeguards against runaway trains. The plot of a train having the engineer get killed, or keel over, or the throttle handle broke off by some nefarious character is incorrect.
I don’t know where script writers get this one, but the idea that you can be alone in a library with a librarian and you can just purse your lips a few times at her and she will just take off her glasses and take her hair out of that messy bun never happens! Get it together writers!
I’m pretty sure that only happens on Brazzers and James Bond movies…
Not everywhere. We’ve had a few speed accidents and last station overruns in the NYC metro area in the past few years.
The 2010 movie Unstoppable was based on an actual incident — CSX 8888 incident - Wikipedia
And another one just happened. Professionals charged with keeping a civilian protected leave civilian unchaperoned. Surprise! Civilian slips out the back door to take care of something he thinks he has to do.
The audience has seen it coming like there was a flashing neon sign.