Average of 6 people involved in an interview loop. Let's say they make $250k a year each fully loaded on average (at the FAANGs, I'm probably underestimating). There's a 30-minute prep, a 30-minute debrief, the actual hour long interview, and probably 15 minutes of writing up the notes about the interview. Let's call it 2 hours. Taking the rough 2000 hours a year, that $250k is $125 an hour. So $250 per person times 6 people is $1,500. Times 4 companies is $6,000. Now, trade that 10 hours back for tickets. Who knows what the tickets would be, but it's 10 hours of work, with some likely positive ROI. I won't pretend to put a value on that, but it's non-zero.
He openly admits that he had no intention of taking the offers for these companies. He just wanted to test his cheating tool to see if it would work.
If that doesn't scream theft to you, I don't know what would. And sure, can FAANG pay the bill? Yes. But should they have to? What if he did it at a tiny 50-person bootstrapped startup? Can he be called a thief then?