I turn the machine length to 0 and stitch in place a couple of times. So far none of the quilt stitches have come undone. If the thread is a stark contrast to the quilt then I would probably bury the ends. I have seen Paducah entry quilts close up and most of the machine quilted ones have the tiny stitches at the start and stop. Most of the quiltmakers , if present, will let you look at their quilt close up and I ask how they do things.