Tower Challenge Exploit by Clans

There are clans that are able to utilize 2 fully active alt clans (100 activity) to protect themselves from tower challenges. This appears to be an exploit of the system. Merely having 25 people with 4 other accounts and only needing to log on for 5 seconds to “appear active” provides this rating which then prevents any other clan from challenging. This needs to stop.

Not sure about this problem. My clan actually has 7 clans challenging our tower this week.

how does this effect tower challenges? Im confused what the issue is

If you are the host clan, and also have 2-3 alt clans, so long as they have 100 activity and challenge your own host tower. This prevents any other clan from getting to the challenge phase, thus protecting your tower. Yes other clans can challenge but what matters is the activity level and the order of challenge.
We have a particular clan on Silver Spire that does this pretty much every week to protect their fortitude tower from being hit by another clan. The reason this is exploitive, for the towers that can be opened for the sake of extra rewards, they are protected via this method. Im Just speaking from experience.