Reserve Bench for Guild Challenge Matches

Hi, how do people feel about a possible reserve bench Guild Challenges.
It seems there is no mechanism in place to replace a team if it's found that any team can't or won't play, for whatever reason after they have been picked and once the challenge has begun.
We usually find who's not taking they're turn in the final hours of a challenge, so an ideal time for quick replacements to come into play.
We all have teams waiting in the wings most of the time, so why not make the numbers back up to a full squad once the challenge is in motion.
Far more interesting when a challenge is hanging in the balance, rather than just sitting there knowing your going to lose because of non starters.
So a reserve bench in effect.
Good for the guild members
Good for the game.
I prefer things that encourage game time and gaining an advantage of being active. I do howevery wish there was a way to not put yourself in gvg for a temporary time if you are on holiday, but nothing during the live part of the gvg. In clash of clans for instance, you can opt out of wars if there is any reason you don't want in. But once again, I want to keep playing this game, for me to keep playing the game so I want people who ate playing to be as active as possible therefore I don't like the reserve bench idea. But an opt out option prior to match being made would be great