Little bit late to the conversation.
Between friends and guildmates it should be fairly easy to prevent sniping, just ask the others not to do it and if they don't like your decision and don't want to follow that simply cut them off, nobody wants a rude friend/guildmate/neighbour. The problem mainly lies in not being able to cut off neighbours. We have a medium-sized Guild in Rugnir and we recently started leveling Arcs but we are having troubles getting all the BPs needed for next level since people who have lvl 70~80+ Arcs can jump in without any warning and steal all the progress simply because they get the 90% bonus. It helps our Arcs level up much faster at no return cost sure, but it also slows down our progress towards higher levels considerably when they starve us of our much needed blueprints.
I would propose an additional feature next to the Ignore setting which would outright block them from contributing to your city. This could be considered broken if all interactions were blocked so I would suggest this additional Ignore function be named something like "declaration of war". This would block them from messaging/aiding/donating to you and vice-versa so you can't aid them for a set amount of time(maybe a month at a time). Now for balancing, the person who gets targeted by this declaration of war would be able to plunder your city 2-3 times per 24hours instead of the normal 1. OR their army gets a big boost to their %attack when versing your defending army. Or both of those things, I'm not a master of balancing
A smaller suggestion would be blocking a person from donating to your city GBs for 7 days(and vice versa) if you attack their city and kill a certain percentage of their army(even just one unit). Simply attacking their city would maybe be a bit too easy but having to kill some of their army would be more balanced for the purpose.
Man I'm so salty towards those players... I just want a way to block them.
"Secure your spots-" That's what I'm trying to do
I realize that higher ranked and leveled people should have an advantage over others but not being able to do anything at all is beyond frustrating