Base inside rocks

I play on Facepunch Singapore II i have seen many players and clans who make bases and loot rooms inside rocks which are impossible to raid. What i mean is that we cant raid them and they can do whatever they want ,they can even shoot from inside we cannot do anything about it

http://tinypic.com/view.php?pic=213klq9&s=8#.VhL19ehVhBc [Proof of a rock base on Singapore II server]

players who got rock bases

just build high external walls all around them…

@el kapitan we cant put walls they put tool cupboards inside these rocks and mostly sometimes they even make a decoy base on top of a rock

just put the walls way around the rock, where you can build, just takes 5 guys with 20 walls in the wallet and the wall is built in 20 seconds

They have a huge decoy base around the rock. We play on official server and we will need atleast 50k stone to cover up their base, because the building radius is quite large and it is a headache to farm that much and spend on a wall. And moreover, if they break atleast 1 of these walls then they will put a door there and we have just gifted them a free compound wall.

how they get in ?