Wow. I had no idea I was supposed to be doing this. I chain piece so I don't typically have much in the way of extra lengths of thread, but I certainly don't fuss over loose threads coming off the end of fabric. Between those & some of my buried quilting threads that I occasionally will lazily bury on top, rather than pulling to the back, there definitely are threads that will show through the white/snow/yellow fabrics when wet, but they usually aren't noticeable when dry. If it's not a show quilt, I totally wouldn't worry about them!
But I guess I'm in the minority.