Bukkit

What steps will reproduce the problem?
1.  Hide your (the block i use is a sponge) sponge with /ps hide
2.  Unide your block.
3.  Push your block with a piston
4.  Type /ps unhide.
5.  Profit

What is the expected output? What do you see instead?

What version of the product are you using?
1.8j
Spigot 1.6.2 (1108)
WE 5.5.7
WG 5.8

Do you have an error log of what happened?

Please provide any additional information below.

This has been a known issue for well over a year, and so first I created a autohide option, then later I created a piston blocking function please read the Configuration Page and the other documentation before posting, PM'ing, or creating Tickets.

@AxelDios: Go

Could you point out ware this is ? I don't see it any ware in the config page or home page.

@jeff1420: Go

This is from the Additional Settings section of the Configuration Page:

Region.BLOCKPISTONS If you set it to true, all blocks moved by pistons are checked to see if any of the blocks are in the ProtectionStones Blocks List (meaning a material that could be used as a PS), and if they are the piston won't move. This is set to false by default.

This from the same section:

Region.AUTOHIDE: Automatically hides ProtectionStones after placement, defaults to false.

You can disable a player being able to unhide the blocks with the /ps unhide command.

Please also read the Permissions Page.

Either use one of these or both to protect against those kinds of exploits.

As an added note, you are using an old copy of PS 1.8j.

The current version is 1.9c, you should upgrade.