[throwaway98797]

let them launch and fail

it’s the only way they learn

[Lalabadie]

"Prompt more" is my default answer now.

Your 80% of the way there? Keep going!

If they're satisfied with the result, I save myself a reluctant client.

If they realize the difference, I save myself an explanation and we can start talking about good foundations.

[make3]

they don't know that it'll break, that's the problem of course

[gwerbin]

I think the point is that those are the clients you don't want, so you encourage them to select themselves out of working with you. The fact that it might be bad for their own business is not relevant to you as a consultant.

[make3]

I think it's normal for non-technical people to have no idea of how things work and of what to expect. It's our responsibility to communicate. And, within reason, theirs to listen.

[Lalabadie]

This can only happen if they have reason or motivation to trust the expertise, and an expectation that the relationship can be fruitful.

Like you said, they must at least be willing to listen.