I've had my run in with customs. Couple of years back I tried to have an airsoft Thompson springer sent through the mail from the US- and customs seized it. (I had managed to have a few airsofts sent through the mail labeled as "sporting goods" or "plastic toys" without any problems before this).
After a couple of weeks of the Thompson not arriving, I figured it had been pinched. Eventually I got a letter stating I had attempted to "import components for a replica firearm". Needless to say it freaked me out as I thought I was in a lot of trouble.
Few days later I received a second letter from the Prohibited Importations Unit. Basically saying the Thompson was a no-no and giving me 3 options:
1- Appeal the seizure (really no hope in that).
2- Abandon the gun and allow it to be destroyed.
3- Export the prohibited item back to its place of origin.
It further explained that exportation can only be allowed using a Canada Customs Bonded Carrier (money). But in order to do that, I would first need to apply for an export permit allowing me to export the prohibited item out of Canada (more money). Export permits are only given to people with business licenses- so I would need to obtain a business license to apply for an export permit (even more money).
Really no choice there. The cost of all the licenses outweighed the initial cost of the Thompson. I had to call this an expensive lesson learned.
The letter stated that the item would be destroyed after 90 days if no reply was given- that was over two years ago so I guess I didn't get into any real legal trouble (thank God)!
