In Clash of Clans, once a war is started, and you're opted in, then you're locked in until that war finishes 24 hours later.
If you leave the clan and join another, you're flagged as still being involved in a war and cannot join another until the previous one finishes.
Why did Supercell impose this rule? Because it prevents precisely what has happened here.
So if Supercell can figure this out, why can't CG?
When a raid starts, put a 24 hour timer on it - or 48 hours - or whatever fits, according to CG's original intention to slow down progression.
Players who participate in a raid are locked in until the timer expires, solves the guild hopping issue as well.
It's really not rocket science, the industry standard has already been set and it's been working for years.
