Stop at US customs before you come across and there are probably some forms you can fill out to prevent grief on your return. At least its worked that way when I've taken new camera's and binocs the other direction when I have not had receipts.
US customs tends to be a bit tougher (except for a couple of the women at Rooseville). Last time Doug and I came across, the US agent described one woman he stopped and asked for ID. Her reply was "don't you think you're taking this too seriously son?"

don
: I would have to agree with you there.

: Never thought of that, and I've taken my boat to Canada twice. If I ever
: re-varnish it and make it look new (now it's pretty clear it's not a newly
: purchased vessel!), that would be a good idea!!

: shawn