I work for the CFIA and we work quite a bit with both the Canada Customs and the Border Services Agencies. If you are caught trying to bring something back and you are knowingly breaking rules in the applicable Acts, you will be penalized and put on record. You will likely be targeted for future inspections/investigations (whether at the border or after you return home).

So...be careful of what you try and smuggle back. There can be very very very very very severe penalties for repeat offenders. Everything that they record is kept for a minimum of 7 years.

"False declarations and the seizure of goods

If you do not declare goods, or if you falsely declare them, we can seize the goods. This means that you may lose the goods permanently, or that you may have to pay to get them back.

Depending on the type of goods and the circumstances involved, we may impose a penalty that ranges from 25% to 80% of the goods' value.

The law also allows us to seize vehicles you use to unlawfully import goods. When this happens, we impose a penalty you have to pay before we return the vehicle. We usually seize commodities such as alcohol and tobacco products outright when they are not properly declared, and you cannot get them back.

We keep a record of infractions in our computer system that can influence the customs inspection process. If you have an infraction record, you may have to undergo a more detailed customs examination on future trips."

Source: http://www.cbsa-asfc.gc.ca/E/pub/cp/rc4044/rc4044-e.html#P274_18115

Cheers,
Trevor