税务居民是由居住时间决定的,不是由身份决定的,留学生都是税务居民,居住在中国的父母不是。非居民在加拿大买卖房子的增值部分理论上应该交税:
http://www.cra-arc.gc.ca/tx/nnrsdnts/ndvdls/nnrs-eng.html#txblgtns
“As a non-resident of Canada, you pay tax on income you receive from sources in Canada. The type of tax you pay and the requirement to file an income tax return...