Several years ago, a guest on Simply Quilts said she always makes a insignificant flaw in her quilts (like you describe). It was her own private joke and often she would ask the recipient (months later) if they found any flaw. Rarely was the answer "yes" and they would have a good laugh and, according to her, the quilt became even more special to the recipient.
Works for me...., as long as it doesn't detract from the design of the quilt