They'll take a boat ride and go around it. They'll bribe soldiers to look the other way for a while. They'll stage multiple diversions along the wall. They'll have their associates inside the US stage diversions. They will destroy or steal sensor elements.
Sorry, Jethro, but you are not thinking this thing through in nearly enough depth.
The last time I looked it was land locked, save for a small section of the Pacific ocean.
Try again....