For me personally, honesty is an inherent part of not being a cheater. I cheated in the past, I don't want to relive that nightmare.
So I wouldn't allow myself to get into a sexual situation with someone who didn't know my poly dynamic.
But-I'm also not a solo-poly person. I am married with a live-in boyfriend and children. So I don't even date someone who doesn't know. It would be disrespectful to my existing family.
As for the risk-adding sex to a "prospective" job situation is always risky.
"Love As Thou Wilt"