I'm not a fan of AIWB. But the second rule is "negotiable" in some circumstances.The entire premise of appendix carry completely contradicts the non-negotiable 2nd rule of firearm safety: "NEVER point a firearm at ANYTHING that you're not willing to destroy or kill."
I've carried pistols in a shoulder holster before while standing in lines, and I've been upstairs in buildings, hotels, and apartment complexes with pistols on my hip, like everyone else I know.
Maybe I'm selfish, but I don't like the idea of pointing pistols at ME when holstering. This tends to be where most of the NDs that I know of have taken place.