ok, so back in dec 2001, i found myself stuck in detroit not knowing a soul and still a bit green on the train hopping thing, and i ended up sleeping in this junkyard near downtown for like a week (i was sick as hell, mild pnemonia i think) but this junk yard was right on the river, and i was looking across at windsor every day thinking, "i can practically see through the apartment window across that river". i watched that river for hours thinking about how easy it would be to float a cheap rubber raft across to windsor. there was hardly any water traffic on that river.
i still believe there are lots of places like this you could cross over, with virtually no chance of getting caught:
https://maps.google.com/maps?q=detroit&hl=en&ll=42.30569,-83.089342&spn=0.035484,0.084543&hnear=Detroit, Wayne, Michigan&t=m&z=14
^^ approx. location of junkyard. it's about 2000 ft between detroit and windsor. you could easily paddle that in an hour or less. and in the middle of the night? not a soul is going to see you.