Didn't trust it till I tried it myself, right?

Totally, that little thing saves me every time, way better than guessing!

And that diagonal wire thing is exactly why I stopped trusting the beep alone, the cheap ones can't see through thicker patches or weird framing. Mine missed a live line behind a metal mesh patch once, and I only caught it because the voltage pen went off when I touched the screw. These days I treat the stud finder as a hint, not a fact, and honestly a strong magnet for finding nails has been way more reliable for me in old plaster.