Yes Customs will 99.95% of the time confiscate the gun.
Yes, hundereds of people have ordered from japanese sites and had their guns seized. I can count the guns Ive heard of comming in though customs safely on one hand.
Years ago (around 2000) I ordered a M11 from a US distributor. I ended up losing my cash and the gun. Shortly afterwards I found this website and have since never ordered a gun from overseas.
Here's some free advice. goto a game and meet the people and learn about the structure around your parts. If you just want the gun for plinking I highly suggest you contact one of the reputable retailers in canada or check the private sales. Alot of the retailers can obtain special orders, just don't be surprised if you pay alittle extra for it.
Good luck and happy trails.