The question is a hypothetical "what-if" question, not a choice I actually have right now.
I work closely with 1-2 team members on developing a software by our company for the customer, on-site with close customer interactions, all as part of the same contracting company. My teammates have been severely slacking, which the customer definitely noticed, but hasn't pushed a red button yet. They are however very pleased with my work and productivity, and don't miss to acknowledge that. I enjoy the customer and the project I'm working on.
Due to culture problem reasons I'm leaving the company soonish. As the bus factor is quite low and resting on me, i would definitely not be suprised (due to signals) if the client became so fed up afterwards, that they contact me separately and offer me to continue working on the project independently before they'd ditch my current employer.
However this project is supposed to be the "entry-step" into an industry and this client for the company. I have a very good standing in my current company, which would be an good spoken reference for the future, but not a well known name. "Stealing" the project would definitely ruin that relationship, but would in turn give me a much more prominent and well-known, established reference.
I'm pretty sure it'd be an severe dick move on my part - but it could be a huge gamble that could have a huge payoff.
So my question is, would it be a huge ethical issue to accept such an offer? Would it even be worth it?