As a seller from the USA, this just happened to me and the person who won my auction. Everyone here knows the fees UPS charges are outrageous considering the USPS/Canada Post alternative. However, whether UPS's fees are ridiculous or not is purely a business matter up to them. The real outrage/scam/shadiness is the fact that they do not tell the shipper beforehand what they charge in brokerage fees.
I sent a package at a UPS store, and they didn't even mention the existence of any taxes/duties/fees. I'm currently battling them after they refused to deliver a package worth $60 unless the buyer paid $59 in fees/taxes. The joke is that they want $80 to return it to me...
I called UPS international to see if perhaps the UPS store I dealt with was just a case of local incompetence, but apparently it's not. I called to get a quote, and the rep had a canned "this rate doesn't include applicable taxes, duties, and brokerage fees" tacked onto the rate quote she gave. I then asked, "what are the taxes/fees etc going to be?" She said, "well they vary and nothing is standard so I can't say, but let me get the number for canada border services." I said, "Oh, so other than the cost to ship it that you quoted me, the only other fees are taxes charged by the canadian government?" "Yes."
Not only that, but the exact brokerage fee UPS charges is available on their website. So it's obvious they don't even train their own employees to know about the fees they charge. It's a very messed up situation that UPS probably wants to keep that way simply because if everyone who wanted to ship to canada knew of the rate differences, no one would use UPS.