The objective is the leave the tube in but make the system in-op. The clevis pins keep the exhaust out of the tubes...Joe

I tend to remove the stainless injection tube, put them in a bag saved for future use as needed, & install a suitable mechanical "plug" (i.e. Nail, Screw, Clevis, Machined plug) UNDER the Nut of the Smog distribution Pipe manifold or "Tree". I see no reason to leave the injection tube flapping in the breeze of the exhaust gases path.
I do not like the PaceCar jeff method since it potentially damages the manifolds (Tube) female tapered seat.

Good topic with Lots of great ideas and a variety of methods.