Well i would like to say this will be nice but it wont. i do not have an afk contraption, i have a room with spawners a mob drop useing spawners you <the server> sell to us. now dragoon is saying i cant stand there for my 15 mins you <the server allow> while mobs spawn. its not like normal mob spawns <spawners you have to stand with in 16 blocks> so how is this breaking any rules. if you dont want people <i no i am not the only one i no of a helper and staff that have spawner mob grinders> standing near there spawners then why the heck do you sell them. what next your going to say we cant build on the server. you allow spawners but wont let us use them to their max. no matter what player in order for there spawners to work they have to stand with in 16 blocks.
so if you cant sit near a spawner, someone please tell me how you suppose to do them ,,, run around in circles above them. trust me i am not trying to be funny.
When I was a donor/helper I wasn't afk in my spawner or just standing in it for 15 minutes. I put the spawner where I most active on my island. It seemed to work fine.
You could make others activate it for you. Give them a reason to be on your island and put the spawners under the floor. You have that amazing shop. Perhaps you could put them under that so when people warp there it activates the spawners?