I'll be an A lister in 3 segments, i.e. next week. I'll earn a CP in first week of December. Frankly, if I were traveling with ANYONE who wasn't entitled to board early, and I wanted to board early (either because of a sense of responsible-ness, or simply because I didn't want to send them through alone), I'd simply forget my desire to board early and board with them.
Gosh, I understand earning a benefit, but unless and until WN adds that as a benefit of CP, your companion / travel partner / friend / kid / etc. isn't entitled to it because you are.
I don't agree (at all) that WN has any duty to move them up to your status for that flight, and I think it really demonstrates the character of the person trying to slide someone through when they don't deserve it.
Having said all that - if WN adds it as a stated CP benefit for designated CP holders, I have no issue whatsoever with both boarding early... (or skimming past the slow line at security).
Sometimes I am really suprised by the feelings of self-importance I see demonstrated at the gate when I'm flying... Humility is gone...