A Short Question About Tunnels

Dummycrats claim walls don’t work.

If walls don’t work, why do the smugglers go through all the effort to build tunnels under them?

By the way, I have been notified that drones can work… if they are armed with Hellfire missiles.  Helicopters work real good too… if armed with machine guns and rockets.  They would certainly be very effective, but I don’t think it would be such a good idea.