Gate checks IME have never stopped on US bound international flights. Every flight I've been on from Mexico bound for the US always has this routine, and with four or more people, you have at least a 1 in 3 chance of getting "selected" and put through an utterly inane search. I guarantee that anyone who wanted to could get a knife through one of these inspections with no problem.

I get very frustrated and annoyed sometimes, but I do try my best not to take it out on the people conducting the inspections. These folks are just trying to make a salary and put food on the table, not fight constitutional battles on our behalf (especially in other countries! ).