Why not just raise the age limit? Adults don't start smoking cigarettes; children do. Younger teens get them from older teens (friends and relatives). Lots of 15 year olds can find an 18 year old to buy them tobacco, but significantly fewer can find a 21 year old to do the same. Canada just needs to copy the US on this. It's simple, highly effective, and can be enacted immediately without any required delay to allow for changes at the factory.