Off the shelf trip flares and flash bangs. :-)
Or a noise of a loudness, type, and frequency that is guaranteed to incapacitate. And that would be on the far outer boundary. The closer to the wall the wannabe illegals approach, the worse things they’ll encounter.
Yes, excellent suggestions. They really are. Not only could our Border Patrol agents place these, but land owners could set them out in hopes of scaring the illegals so badly that they will flee and not come back. And the beauty of it is that when these illegal filth turn around and go back to their towns and villages, they'll tell others that the land, trails and pastures here are full of dangerous surprises. Any and all ideas should be tried to stop and prevent these illegals from sneaking in to rob, rape and/or murder our fellow citizens.