I had no idea this was coming in but as I know a lot of people do indirect flights etc. wonder if it is worth being made a "sticky"

http://www.cic.gc.ca/english/visit/e...m_campaign=eta

From March 15th you need an ETA (even British citizens) to fly or transit through Canada. Until Fall 2016 you can still board the plane with Passport and travel documents but after that will need an ETA. It says you will usually be approved within minutes.