The thread you refer to is an interesting read, but you need to remember a few points:
- Although the poster is a regular contributor to the site and seems to have our best intentions at heart, never forget that he still has an economic incentive to sell what he has;
- Seizure will happen more often than a polite request to turn back and dispose of the goods. Do you think they ask the drug smugglers to nicely return from where they came?
Do yourself a favor, buy from Canadian sources. The extra 10-20% you pay for your piece of mind is worth it.
Also remember to factor in costs related to importation when you say outright it's cheaper to buy from extra-nationnal sources.