those with engineering problems could be where sharpshooters are stationed.
Think that will have the right effect?
Those with engineering problems are going to have terrain or substrate issues and may include riverbeds and flash flood areas, just to pull a couple of things out of the hat.
These areas could also provide alternate incursion corridors, and with the proper staffing and a little infrastructure could be 'roundup' corrals or choke points by which those who do cross would be easier to track and interdict.
(Make no mistake, there will be opportunities for those guarding those vulnerable areas to make a lot of money looking the other way. Redundancy will be needed.)
There will be tunnels in the places the wall can be dug under, likely from a building on one side to buildings on the other. The profit motive exists for the smuggling of drugs.
There are sensors and the capability to detect such diggings and movement independent of solely manned operations, and this could prove to be a good training ground/opportunity for those who may use these capabilities for military purposes elsewhere. The really determined will find a way, but the average person will not.
At that point, because of the general nature of the most determined, (usually felonious), the methodology may dictate more harsh methods and capabilities compared to those used for more ordinary incursions today.