He's right about the "Plan B" at least where I'm concerned: I wouldn't have started Tarsnap if I hadn't received a job offer from Google to prove to me that I had a safe fallback plan.
I don't think Colin means he takes the offer as a guarantee of a position at Google in a few years if he so chooses - although I doubt his Tarsnap and other work have hurt his chances - but rather that it's proof that he can get 'a high paid tech job somewhere'.
