The key here is inactive co-ops. If an account owner is no longer logging into their own account and the co-op is running the account like it is a second one to their own, that is where most of this comes into play.
You can not run a second account (or more) as your own... this is hardly different from multi accounting the only difference is that instead of creating multiple accounts on one world, it is inheriting them through the co-op option.
As you quoted Vivienne, Rev is right -you can not use your co-op rights to benefit yourself. This is pushing. Keeping an account appearing active at the benefit of the co-op .... additional troops at the co-ops disposal, resources, potential villages.... As a co-op you cannot conquer your inactive co-ops villages for yourself.
When I said as a co-op you can conquer villages just like anyone else, I meant that you can drop the co-op and fight your way in by killing off the troops just like you would conquering any other village. "Like anyone else" is like anyone who would be trying to conquer a village. Removing the troops to assist you in conquering is not allowed, putting support troops in your own villages is pushing (advancing yourself by your rights as co-op). My apologies if I did not word that as clearly as I had intended.
TFox you are correct. I get that you all want to secure your tribe from enemy poaching of inactives. Drop the co-op and conquer just like you would any other village. If you drop the co-op you do not have an advantage.
In response to your other part TFox, and Coldog, if the account owner is actively involved in their own account (logging on, showing activity) then as a co-op moving troops is allowed. Again it is when that account is inactive it becomes an issue.
In answer to Viviennes last question: So if you believe a tribemate who you have co-opt privileges has quit, what are the appropriate next steps? Also, what if you really don’t know if they are still active or coming back which realistically is most often the case?
Great question. If you are not seeing any activity from your co-op.... you have not heard from them in chats, when you log in to their account the only activity you are seeing is your own.... I would suggest trying to message them and give them 24 hours to respond. If they do not respond, I would notify your leadership that you suspect a player may be inactive. Log out and do not log back into that account as leadership can tell if that account starts to go inactive by their leadership rights. Most players that are actively playing log in at least once within 3 days.
At that time if that is the case (no activity by account owner), moves can be made to secure those villages by the leadership and tribe mates. I would suggest as the co-op, you drop the co-op of an inactive account. My suggestion. Not a rule. For sure, at the time they show inactivity do not do anything that could be considered pushing.
As far as them gone and not knowing if they will be back, account owners really need to communicate that with their tribe leadership if they plan to be gone any length of time, and at the very least their co-op so the co-op can be aware of what is going on.
Co-op was meant for short term assistance to the account owner. Away at work, school, out for the weekend, even vacation....
Obviously the co-op option has its faults and while it was meant to be a good thing and in many cases it is, it also can be abused and that is where we have to watch what we are doing.
I know you can look at what I said here and rip it apart of take it as you want it. You asked for answers and I am trying to give them.