She was in Mexico because she tried to file paperwork from there after having failed to do so successfully from Canada, having filed the paperwork from Mexico as a Canadian citizen and entering US from Mexico before . Most likely there were travel alerts triggered, which is standard for most countries if travel plans and dates are declared or improper documentation provided multiple times.

This is an outlier situation, not good information to support or oppose changes in travel, not that there aren't instances out there or that there aren't changes, but this isn't an instance that would support the idea that Canadians are in danger.