Scheel’s attack in interesting, because it doesn’t require physical access to the TV, it’s virtually undetectable, and it’s very hard to remediate once exploited.
Imagine your book’s character parking her car outside her target’s business or residence, turning on her laptop, attaching a special transmitter, and tricking all the smart TVs in the area to upload an exploit. Then she could do any of several things:
use the TV’s wireless connection to attack other targets on the same network
join the TVs to a botnet to attack a web site
mine some bitcoins
capture audio using the TV’s voice control feature
Smart TVs are probably like most Internet of Things (IoT) devices. The manufacturer happily staples on all these features to add value but then falls short in addressing security problems discovered later. Have you ever heard of anyone applying a firmware update to a TV? My TVs are a few years old, making them somewhat antiquated. So maybe TV firmware updates are commonplace, but somehow I doubt it.
Do you have a smart TV? Is it connected to the internet?