Claim Blocks are broken in 0.7
As the title says, they are totally useless now.
Either you cannot access them and are told that the area is "contested", even though it isn't, or other players can just build a claim block in your region and make your claim null and void.
Also other players are able to just spawn to your claim block, even if they are not a part of your house or have been given access: tonight on the Top Hat Engineers server players were able to spawn to anyone who had laid down a claim block, regardless of permissions.
Tested on both single player and multiplayer, the Claim blocks just don't work now.