You usually see these on fields that are co-owned or need to be accessed by several municipalities. Everybody gets their own key but can still have access to the area whenever needed.
I hate to say it but shitposts and circlejerks are a bit part of my reddit browsing to lighten the mood. Otherwise, trash like terriblefacebookmemes and idiotsincars was great entertainment for some reason... I don't know why I am like this.Edit: to extend on this, seeing a post about some crazy shit play out and then reading everyone react to it is so much fun.
You usually see these on fields that are co-owned or need to be accessed by several municipalities. Everybody gets their own key but can still have access to the area whenever needed.