To be clear: The stock was confiscated by US custom and he received a letter stating they were thinking of sending him to jail.
After getting a few more details it looks like nothing will likely come of it, but the guy is holding his breath for a bit.
After reading through this thread, my initial thoughts are that the seller is scamming you and using ITAR as an excuse. When an item is shipped from the US it is transited through whatever postal service you used and turned over to Canada Customs. It does not go through US customs. Canada customs ensures that the item is not on the prohibited list, and once that is confirmed,they are only concerned with collecting the appropriate duty. They are tax collectors with guns and that's it. Nine times out of ten, when they hold an item, it's because the value is not appropriately listed and they are trying to figure out how much to tax you. This happens when people declare the items as gifts on their US Customs forms, or list a low value and then insure the item for 10x the listed value.
If for some reason US customs was doing spot checks, or was specifically targeting the seller, then both seller and buyer should have received a letter in the mail outlining the seizure. I'm guessing that US customs does not run $100,000 surveillance and interception operations to get a $200 UBR off the certified ranges of Canada.
Miracle Joe, I challenge you to do the following:
1. Request a copy of the letter from the seller. A scan can be emailed to you, as can a photograph.
2. Post the letter in this forum with the sellers personal information edited out.
Also, if anyone can post a single specific example of a person in Canada, or the US, who has been charged for violating ITAR for an individual item, or small quantity of personal items, I'd like to hear it. I'm not saying that CGN members should not respect ITAR, but the fear mongering on this site, sometimes gets a little excessive.