I would want to know, but I would probably like a PM rather than a post!
I'm sure you could word it gently ;-)

If it was already quilted.. I would prefer to live in my ignorance. Since repairing a block once its quilted and having it look like it never happened is really risky.... I would just as soon not know.

Personally, I wouldn't care one way or the other. If the quilt was all finished, then the boo-boo probably wasn't that noticeable to begin with, and even if it was a gift, there is no way I would take it apart just to fix one little mistake.

While I don't make it a point to create errors in my quilts, I actually think a little slip-up now and then just adds to the charm of a hand-made quilt. None of us is perfect, and our creations are not perfect either. It's the meaning behind the quilt that matters the most.

I would want to know if I made a boo-boo. Heck I might ALREADY know! LOL

Letting me know would help me avoid the same mistake in the future...It might not change anything on the quilt, but could impact future work

I'd like to know. I made a huge error on my son's wildlife quilt and I never noticed until I saw its finished picture. It is now a design decision. I planned cornerstones in the borders so the flying geese wouldn't run into each other turning the corners. Two opposite corners have eagle blocks and the other two have colliding geese. At least they aren't on the same side. I can't change it and he wouldn't care if I did tell him, so I'm okay with it. I did learn something so all is not lost.

I would want to know so I could then decide what I want to do with it. If I had planned on giving it to someone who had an eye for quilts, then I'd not give it to them, I'd give it to someone else. I'd be embarrassed if I gave it to someone who knew about quilting and received my blunder.

Would I want to know? Yes, but that's because it wouldn't bother me. Would I tell someone else? No, because it might hurt them.