Not at all, some POS systems will account for rounding, but most don't. One only needs to look at your receipt to see if this is the case. Cash registers are nearly always out a dollar or two at the end of the day anyway, that's normal, and cash rounding doesn't change that much.

Also, in Canada, I have never seen those automatic change-making machines that are common in US convenience stores. Cashiers always count and handle cash by hand.