Unfortunately, it doesn't even matter. If the reader detects that you have a chip card, you cannot use the magstripe even if your chip is faulty. The error you will get, after swiping the card, entering the amount and then pressing enter waiting for confirmation will be "PLEASE INSERT CARD". Quite vague but that's exactly what you get.
I do not know of any readers that won't let you bypass this. Many terminals have a button that literally says "bypass PIN" that'll let you use the stripe in case the chip fails.
Interesting. I was using my chip card in a country where chip cards were not really well known till last year. Surprisingly they already had chip-ready readers for easily two years before now so I have personally experienced the part where the cashier is completely baffled with the face of "I've never encountered this error before". Then, I have to operate the terminal, and insert my card (again) and press enter. I do not remember seeing any way to bypass it. I would have loved to do that because by this time it'd already be in my wallet and I cba to remove it again.
