Waystone Abuse Prevention

Hello! Recently my group and I have been observing people "disappearing." To give them the benefit of the doubt and avoid accusing people of hacking, we think they're waiting to use a waystone invite until they're in a fight about to die.
To prevent unfair fighting, I think it would be a good idea to make either a time limit of when you can redeem a waystone invite, or make it so that you can't activate it when you're in combat (the same as how there's a combat timer log too).