My mother-in-law recently got her visitor visa approved and is in the process of buying an air ticket. Does she need to buy a round trip air ticket or can she buy one way? I am worried that customs may reject her entry on the grounds that her intention is to stay in Canada if her ticket is one way. However, she may want to extend her visitor visa near the end of her visitor term and that's why I would like to buy a one way ticket for now.