I wrote that to encourage you to check it yourself in real life. But below you will find a picture I have taken myself a minute ago, the string is just for reference - it IS out of focus so the mirror is out of focus too. Only "bg" is in focus. :)
My argument in such cases is always the same - without it you would be unable to see anything when using SLRs or periscopes. They have a mirror inside, and it is very close to your eye, right? Or you can also imagine that every flat mirror is like a hole, in which you see flipped reality. :)
Conclusion: Corona's DoF is real, fake DoF is fake.