1 week trip to South America raises red flags for US Customs to be vigilant with luggage as well as passenger due to many reasons like trafficking drugs and exotic animals...etc. If you register with Canada Gov your travel dates and provide address of family members you will visit...etc. and make sure your suitcase does not smell food or drugs or ...etc and that contains no food or other items that US customs MUST check when returning to US and on your customs entry form or app mark you have nothing to declare then if and only if you have no previous convictions then usually luggage passes through quickly...