I live in Windsor Ontario, so we cross the border alot!! (in car only w/o trailer)
Many of our friends work in Detroit and they do have their lunches searched and/or are asked 'what's in the lunchbox' on a daily basis.
When we need to pack lunches for a day trip I always put BP & Jelly in the cooler, and hide the turkey and ham sandwiches in a compartment in the floor of the truck.
They are also picky about children in the car, and will ask the children several questions to ascertain if they are safe or not ( a good thing to me!!!!!)
We have never been pulled over for anything, and never/rarely have to pay duty on our purchases made in the US. We have had only good crossings and I honestly think it is due to the way that my hubby interacts with the customs officers (either that or he has an honest face).
I have however heard many a horror story from people who have had BAD experiences, at the border =[
2010 Dodge Ram 1500
2012 Rockwood 2306
DH (Alan), DD (Madison) and Zoey the lab,