Comment by thaumasiotes

No, it says that projects should move forward without verifying that prerequisites have been fulfilled, but that the verification should take place anyway. It's about the pace at which you can go.

Trust-free:

    Ensure that step A can go off without a hitch.
    Begin step A.
    Ensure that step B can go off without a hitch.
    Begin step B.
    Ensure that step C can go off without a hitch.
    Begin step C.

Trust, but verify:

    Begin step A.
    Begin step B.            Check that you have whatever you need for step A.
    Begin step C.            Check that you have whatever you need for step B.
                             Check that you have whatever you need for step C.

You can't finish step B until you have all the prerequisites, but you can start it.