> But let's say employee names fail on apostrophe. Won't you just have a unit test that sometimes fail, but only when the testing tool randomly happens to add an apostrophe in the employee name?

If you just naively treat it as a string and let hypothesis generate values, sure. Which is better than if you are doing traditional explicit unit testing and haven’t explicitly defined apostrophes as a concern.

If you do have it (or special characters more generally) as a concern, that changes how you specify your test.