It is a slow trend, but I have been seeing it in Canada now as well (maybe not in PEI, but definitely in Toronto) with a lot of newer businesses, typically food and beverage establishments.

If almost all of your customers are not using cash, there is definite rationale for not accepting it. Cash is expensive to accept when you factor in additional time needed to count, go to the bank, bank fees for making deposits, potential for employee theft, robbery, loss, additional security costs etc., that in more and more cases makes it more expensive than the fees associated with accepting card payments.