HI, I am a Canadian Nurse who lives and works in Michigan. I travel across the border every week with my son to see his father. I have nvere been asked to show my visa screen document. I do have to show my TN Visa ( I-94) and my ID but the only time I have been asked for a Visa Screen Document was when I applied for a new TN recently...and even then because I was renewing before the July 26th date, it was not a requirement. If you have the document, bring it with you. If you do not apply for one today online at cgfns.org. If it is in the mail, and you plan on being back into the US before the July 26th date, you should be just fine! If not, contact the port of entry and ask for more information, they are very helpful...be honest and ask as many questions as you need to to understand...they won't mislead you. Good Luck and Safe travels!