It happens all the time. I ask by when do they want it finished and no matter what the date they give me, I say I can't get it done in that time frame, so sorry.
I am asked too repair all kinds of stuff from new elastic in shower caps to re stuffing animals. I tell them I am a quilter and just don't know how to do that kind of work.
I also agree with HEN3ETTA. quilting is an art not a hobby even if we call it one or think it is our "hobby".
peace :D