Oh that's good to know...user828 said:.that is not an issue, she would simply enter Canada from US. Infact, lot of people are already in Canada ( for eg, parents ) when this occurs and there is a process called "flagpoling" where you go to US border, and say I want to flagpole, they refuse admission to US for administrative reasons and then let you reenter Canada with a U-Turn and they finish the process, in her case, she will entering directly from US so no issues
Flagpoling is typical when you don't have US visa, else just enter US and make a u-turn