I think those concerns are very minimal. When a Canadian or anyone in Canada enters the U.S. at a land border crossing, it's in fact that individual who's providing his or her personal information to the Government of the United States and essentially agreeing to the laws of the United States with respect to the use and storage of that information. It's really difficult to envision how the fact that the United States then sends a record back to Canada saying this person has just left Canada would impact an honest, law-abiding traveller.
On October 5th, 2017. See this statement in context.