I have been a hand quilter for almost 40 years. I always knot. I make it as small as possible and make sure I pop it through the top surface so it is hidden. I have quilts I have used for years without any of the knots coming loose. I noticed just today when I made our bed a thread hanging. I believe my cat is responsible as he gets his claws caught sometimes. I am not going to worry about it. Should a whole thread come loose I will just requilt that part.