It also needs deep water, ferries serve the island, and planes fly overhead. People around are interested in boats. I think a sub near the island would have been noticed. Puget Sound is a busy waterway.
Thats some criminal behavior for white hats.
The acrobatics are what make the employee for a joyride unbelievable. Everything else could have been doctored, covered up, or explained away. The best way to send the message that planes can be hacked.
The youtube audio seems heavily edited, he is talking to the pilot at some points. Like only select quotes were pasted together.
Yet another audio of the Q400. This one has the traffic from other planes communicating with ATC, edited out of some of the others.
https://youtu.be/xABpLjK6_2Q
23:55