Problem is you don't know whose code you're stealing, which leads to all sorts of legal, security, and correctness issues.
No. GitHub Copilot tries to understand your intent and to generate the best code it can, but the code it suggests may not always work, or even make sense. While we are working hard to make GitHub Copilot better, code suggested by GitHub Copilot should be carefully tested, reviewed, and vetted, like any other code. As the developer, you are always in charge.
EDIT: the text above is a direct quote from the Copilot website
Naively, as someone who just heard of this - that sounds worse than useless. If you can't trust its output and have to verify every line it produces and that the combination of those lines does what you wanted, surely it's quicker just to write the code yourself?
Basically, in order to fall victim for this "code theft" (or any other "footguns" from Twitter threads) you'd need to be actively working against all the best practices and common sense. If you actually use it as a productivity tool (the way it is marketed) you'll remain in full control of your code.
By typing “fast inverse square root”? That is hardly an outlier or manipulating the machine