I didn't reply to the previous post, but did think about it ;-) . My opinion is that there were 3 'classes' of quilting issues: (1) a piecing error where a block was obviously turned the wrong way 'round and (2) excess fabric issues, either puffy blocks, puffy center, or wavy borders and (3) Backing or Batting provided was too small.
If it's a piecing error, I would say that 100% of the time the long armer should stop and call.
The too much fabric issue is a grey area. I worked with a professional quilter who would routinely fix these as part of her quilting service and never call the customer. As far as they knew, she just quilted it out. The down side of this is some customers continue bad habits (especially the wavy borders).
Issue three would probably also be a stop and call. I wouldn't trim the top to fit the backing in case the quilter was aiming for a specific measurement. If there were enough backing where you could cut a strip from the length and add it to the width (or vice versa) I would suggest this, but mention that there would be an additional charge. Most long armers charge extra for seaming a backing.
The kindness you did by fixing the top went above and beyond your job description, and it sounds like you didn't alter the size of the finished quilt, just squared it. I would just explain the problem to her. My guess is that she will probably be OK with it.

now I wish someone had took the time to fix my quilt that I messed up. Thank you for doing that for her, I am sure she appreciated it I know I would have.

I don't think you are in trouble at all. You are an angel. I can think of no way that your customer can possibly be upset. Tell her what you did when she picks it up, but only because that maybe next time she won't bring the same problems. Tell her that you just went ahead and took care of it, and you hope she doesn't mind. If she does...well, there is just something wrong with her. What you did is what she should have done before she brought it to you...and if she is having health problems, she probably did the best she could at the time.

Dina

I for one would appreciate your work and fixing my mistake. But I would also tell her so she is more careful for the next quilt not to repeat the same errors. You are a good person to go through all you extra efforts to assure and beautiful end result.

I agree with what you did in this case as she had already tried to fix it!

I have worked with an elderly lady (don't take this wrong, I'm 73 so I am elderly also) anyway she had gone through the depression so was very very thrifty and she brought it to be quilted. She had wavy borders, places where seams didn't meet and the backing was all pieced irregular. My friend and I fixed it and she was very very appreciative of the outcome. Since I don't do it as a business and her eyesight was not too good I did it as a labor of love..

I probably would not do that to someone who would or should learn the correct way to apply borders, which seams to be the most problematic.

What you did showed kindness for a customer who needed extra help. You won't be in trouble for that.

My bet i that she won't even notice thinking that she fixed it herself!

It did take a few hours, but I will not be adding a charge this time. I will explain what I needed to do and show her what I trimmed, cut and added, when she picks up the quilt.

I would say that you went "above and beyond" in fixing this whole mess and you deserve a medal for bravery and honor.