Marines’ possible uniform change: Cloth chevrons

I was in when they started putting name tapes on utility uniforms, changed from OD green socks to black, and boy how the lads howled. Then again when they went from tri-color cammies to the digital pattern. Through the transition you would see Marines wearing, green tops with desert trousers and al manner of configurations. 1st Sergeant heads all over post were exploding in unison. This will be no different.
Personally I am for sticking with the metal chevrons, though they may "hurt" some people, they can function as a lethal weapon at a moment's notice.

How do they come off when one doesn't want the bad guys know their rate/rank?

I think it's a great suggestion to look into for Marines. I always preferred cloth over metal myself as it made uniform maintenance easier and less time consuming.