Even if we pretend this is only about drug smuggling (strawman), I'd say forcing smuggler to dig a tunnel or build a submarine or raft is a substantial deterrent as compared to walking. I know I've never personally bothered to tunnel under a wall. You know why they resort to tunnelling? Because of the rough ridin' wall.
I honestly don't give a crap if they build this wall, but to act like a wall isn't an effective way to keep people out is batshit rough ridin' crazy. It's like saying a roof isn't good at blocking sunlight, because windows.
Those quote were about drugs which is what Trump keeps saying the problem the wall will fix (1st one) and illegal immigration (2nd one)...
And no they aren't building tunnels because of a wall....it's to avoid detection (cameras, people, etc). If you insist on spending money on this when we have bigger problems....instead of spending money on a physical wall get with the effing 21st century and invest in technology.
Legit insanity in 2018 to think a wall fixes anything.