You are wrong.
NAFTA covers items manufactured in Canada, USA, Mexico and for some reason Chile.
But not items manufactured elsewhere (like China) and purchased in NAFTA countries.
Even if an import is not subject to duty, it is subject to federal and provincial sales taxes. Legally this kicks in when the item is valued at $20 CDN or more (about $15.50 USD at the moment).
Used items are not dutiable but are taxable.
In addition, any shipper, including Canada Post, Pitney Bowes or UPS, is allowed to charge service/brokerage fees for their work in wrangling the import across the border and remitting any monies collected. These range from PB~$5 to UPS' $25+.
The $20 level has been in place since 1985, although the Harper Government raised the 'cross-border shopper' limit to $200 a few years ago.
The Canadian public service, in the form of Canada Border Services Agency, made the sensible, if informal, decision to ignore small low-value imports (under ~$100) on the basis that if it would cost more to collect the duty and sales tax than could be collected, it would be a waste of taxpayer money to bother with them.
That doesn't change the law.
Couriers like PB and UPS are legally bound to collect the applicable duty and taxes. They don't have a choice.
That being said , it is very simple to boycott (note spelling) GSP listings.
All such listings have these words :
Customs services and international tracking provided
If you see that, just pass them by.
The GSP is not appropriate for most low value (under $100) US or UK purchases. It can actually be a money saver on higher value items.
