Objects should not be moved at the moment. At the time I made pistons, they weren't going to. This is part of the reason that pistons were never implemented. There will need to be a lot of logic added so that they know what tiles can and cannot be pushed. Currently there are a ton of multitiles that will break (in the bad/glitchy way) when pushed. Now, I will say that, in the time since I made pistons, I have learned a lot more about TileObjectData (it is an internal thing for info about tiles), so I will probably be able to set things up more dynamical which would cut down on the amount of work required to tell what tiles can and can not be pushed. In regards to making objects like turrets and chests pushable in the future, it could be done however, they would have to abide by some rules for how a tile stores it's data. For vanilla tiles, this wouldn't be much of a problem, but modded tiles could have issues.