Will the workers be sympatico with immigrants and do a shiitey job?
“Will the workers be sympatico with immigrants and do a shittey job?”
The companies that are awarded these contracts were pre-screened, based on their proven past performance on similar efforts, and their financial strength (among many other factors).
Those companies are bound by the contract specifications, and there is a formal inspection/acceptance process for them to deliver the final product, and receive final payment.
No process is perfect, if humans are involved, but experienced professionals (US Army Corps of Engineers) are managing this contracting process. They have effectively produced border barrier before.
The bigger variables are likely the strength of the specifications they receive, and the amount of money dedicated to the effort.