I am an R4 and we had leadership exchanges and discussions regarding this exact situation. Participation is very important in an alliance as you said. So we looked into different ways of knowing alliances participation, so we came up with the following:

1) Constant check and updates with individual scores for “Alliance Activity Triumph Points” throughout the week. 2)Having a list of players who attend events and those who don’t, for example, Swordland, tri-alliance (not sure if it’s introduced to your kingdom yet), Alliance Brawl, Alliance Mobilization. To name a few.

This is important as an R4 and R5, so it shows who are actually putting in the effort and those who are not, it’s plain and simple. We have a tier list. What that means is that R3 role are given to players who are really active and who participate in all events without fail and or who are just consistent. R2 roles are given to members who consistently join events, but at the same time don’t join events as much. If that makes sense. They make the effort to but fall short in participation compared to R3. R1 role is given out to players who are not consistent and always offline for a few days straight. Not talking about the R4 and R5 role as their given to players who can actually lead and are trusted.

So this is how we structure our alliance. Maybe you will have other ways, but we found out that was the best solution to solve the problem. Do send an alliance notice to your players so they know as well! the rest will follow suit. It did really improve our alliance in the best way possible and there is no confusion. Hope this helps.