you might want to look around your spot a little better next time you visit the spot and look for cameras if you see any wouldnt return or mess with the plants at all. not sure how bad canada is on cultivation, but in the states law enforcment can set up cameras and film you for months tending the plants and aircraft can be used to determine when you harvest and then they will bust you right after harvest. while chances are its probably just a local pilot out flying around you should be aware that if it only flies over your spot while your there or shortly after you leaving the spot that it may be monitored with cameras and they know exactly when your there.