According to the Toronto Star Scotiabanks visa cards with chip technology are having some issues, especially if you're travelling.
This is really important especially if you're going on any trip where you're relying on your credit card as your cash source. To be fair, apparently this is happening with other chip technology credit cards as well.

You may want to contact your credit card company to see if they've had a similar issue with the credit card chips.

In Australia, you're often given the choice of swiping and signing or using a PIN.

"It was like Russian Roulette, because sometimes the card worked only by swiping/signing, sometimes it worked with the PIN. And other times, it simply didn't work at all."

The problem appears not to be confined just to Scotiabank Visa cards. (Repeated requests to Visa Canada for information on the scope of the problem or how many transactions are being affected went unanswered.)
http://www.thestar.com/travel/article/746978--new-credit-chip-cards-can-be-a-consumer-curse