I easily punch through the 'KO's" using a drift pin and my linesmans' as a hammer. I'll usually support the area around the KO by setting the box atop a fitting.
Caulking around the box, IMO, is a technical violation, as the NEC required a small space between the enclosure and the wall. That's why the boxes have those little tabs at the corners.
Otherwise ... I'm weqary of all this chicken-little BS about "might void the listing." That's pure poppycock, tossed about by ignorant jackalopes who want to pudh others around. Might? How about 'might not?' From here on - either the critic provides a specific letter from UL saying "Doing "X" to product "Y" will void our listing," they can go bark at the moon. No more inferring, guessing, playing it safe, etc. I will nol longer tolerate government by overactive imagination and supposition. They want to document their fears, let THEM do it.