I've have seen it happen, but it's never impacted me much. I'd guess this happens on other exchanges too, but I've not spent much time on the other exchanges.

If it is concerning or causes you issues you can just use a different exchange. Bittrex (not currently allowing new sign ups and requires some personal information it will verify depending on your country), shapeshift, bitshares (https://wallet.bitshares.org), or others out there.

But you'll still follow a similar process as the guide, though the buttons and codes will be in different places.