It's amazing when you read a totally different post and then it forms an idea for something new. I was reading the post on the General forum about ruins: http://community.playstarbound.com/index.php?threads/player-ruins-throughout-the-multiverse.21427/ And someone said about leaving traps in their ruins. Assuming you can choose where to teleport down to from your ship, it would be cool if you could build dampening field generators that prevent other players from teleporting within proximity to it unless they are 'you'. That way you can create a building, fortify it and then put dampening fields in it; forcing others to brave the defenses...instead of teleporting directly inside. Edit: You can extend/control this further by having the generator slowly degrade over time, maybe like 1% per hour. So eventually the dampening field breaks and the ruin truly becomes a ruin...maybe different qualities of generator so you can have longer or shorter degradation periods. Generators made from rare material lasting weeks instead of 100 hours.
I don't think you can control exactly where you can teleport. And being underground prevents teleportation. I'm down for this though.
Since the point where you teleport is essentially your spawn point on a planet, you can probably change it as long as it's outside. Either way different types of force-fields or fields in general would be really cool.