The word used is 'could' and not 'will'. What effort does it take to do it the 'correct' way and it eliminates one possible factor from the equation. I have never purchased an upper without the rings and they are always misaligned.What WILL cause a gun to malfunction is it's cleanliness.
This isn't combat gentlemen. We all have time to maintain out weapons properly.
Use is one thing . . . abuse is another. You weapon is a machine.
There . . finished . . sorry. --- SAWMAN
Cleaning when there is a problem is always the smart thing to do.