My guildies have accidentally left, they would join our guild and when they are in a quest they have to hit X and if they accidentally hit G and then hit X they auto leave. I would love it if Zenemax/Bethesda added a Yes/No option. So if you hit X on accident in the guild window they can then confirm or deny it though.
Some of my guilds also brought up how they accidentally deconstruct important armor instead of being given an option to yes no as well. i believe that is a bit more tedious but is that was an option that would be Yes/No and give them an on off option in the settings.
Anyway the primary issue i have had is the fact that so many guildies have accidentally left the guild because they hit X.