Leskova, Yes, that's the law in Canada. As has been explained by others in the thread, in the US, if the fares goes down and and it's available for the same flights as ticketed, most airlines will give a voucher for the difference OR
for a service charge (now USD 100) issue a difference back to the original form of payment. I'm not sure if this is law in the US or if this is voluntary.
Since US reservation centers for US carriers also handles calls from Canada, there's info on how to handle the situation if point of sale is Canada. Key to get the refund is that the customer has to check back to the airline to see if the fare has gone down.
Boeing 777s flown: UA, TG, KE, BA, CX, NH, JD, JL, CZ, SQ, EK, NG, CO, AF, SV, KU, DL, AA, MH, OZ, CA, MS, SU, LY, RG, PE, AZ, KL, VN, PK, EY, NZ, AM, BR, AC, DT, UU, OS, AI, 9W, KQ, QR, VA, JJ, ET, TK, PR, BG, T5, CI, MU and LX.. Further to fly.. LH 777