I wonder if it's still a crime if the Michigan 17-year-old slips his consenting 15-year-old partner into Ontario, has sex (under the bleachers, say, in the Riverside Baseball Park in Windsor) and then drives back to Detroit.
Yeah, just imagine the conversation at the Canadian border:
"Passports please. Both of you." "Here." "You are both minors. Minors under the age of 18 without a parent must be accompanied by a signed and notarized letter stating the parent's approval of the trip. What is the purpose of your trip?" "Loss of virginity, sir. It is illegal for consenting minors to have sex in Michigan." "I see." "But not in Ontario -- as long as the minors are within five years of each other in age." "I see. Do you have a letter from your parents?" "Yes, officer. My mom provided condoms too." "Alright, carry on."