If you pulled a marble out of a bag ten times a day, with a 0.1% chance each time that it was red: after a day you'd have a 1% chance of seeing a red marble, the first week you'd have a 6.7% chance, the first month you'd have a 26% chance, and the first working year you'd have a 92.6% chance of having seen at least one red marble.
That's not how fair use works. It doesn't matter how unlikely it is, if Copilot one day decides to "suggest" a significant snippet of ckxd from a GPLed app, you'd better be planning to GPL your project.
Probabilities are fun!