Just for anybody that didn’t know, if you have family or friends visiting Canada from anywhere in the world except the USA, as from March 2016, they need to go online onto the CIC website and get an Electronic Travel Authorisation (eTA) visa, before trying to fly.
The only people exempt from this are Canadian citizens and permanent residents and US citizens.
CIC say it takes 5mins and $7 per person to do and the (eTA) lasts for 5yrs.
The (eTA) is available from this month.
At the minute this is not for people using the land border but eventually it will and also the US version (eSTA) will replace the I94.
Thanks for the heads up mate - good info to pass on 
Here is a link to the Canadian Government web site.