I have done that and I still use that slider. It was a fairly small area that I sewed through. I can't really tell any difference. I also quilted a small packet of post-it notes to the back of one of my quilts once. Wouldn't you think you would notice that rather quickly? I did take a picture of the post-it notes thinking I would post it here, but never did. Maybe I can still find it. It seems like I have to make every possible mistake at least once
Found the picture. It was just a small stack of post it notes.