I'm with you on honesty, and I've certainly seen people tacitly trying to pass off AI outputs as human written. But I think we've reached a point where, in lots of contexts, we can't reasonably assume human authorship by default any more. (We can reasonably want it and push for it! I just mean we can't literally expect it.) So even when we would prefer openness, I think 'lying by omission' is too harsh a characterisation for people who choose not to declare AI authorship but don't actively try to cover it up.