David Braben has covered many aspects how the policing will work in several videos earlier on but more details have become apparent especially most recently during the recent BAFTA session on gaming. You can hear it by using podcatching software such as iTunes to subscribe to
Lave Radio and listen to Outside Broadast #1 at 41minutes 22seconds, this is David's talk at the Baftas
Sorry but the Lave Radio website does not seem to list that particular episode for download in the
previous episodes list.
Generally speaking though, if you are playing online and not Single Player online, you will see other human players. Every human player is a member of the pilots federation. The federation cracks onto people that kill or attack it's members.
If you get attacked, the attacker gets a bounty so it is then "legal" for others to attack them to get a bounty.
There are also Police ships which as David puts it "....can be made as powerful as we like". Of course there will be some places there Police presence is minimal though.
You also have a Friends list where the system will favour people on your friends list. If people grief you, they may not appear in your online instance again so you won't see them.
Griefers will eventually get filtered into a group with other griefers where as David puts it, they can grief each other and will probably enjoy it.
This information is all from David's Bafta talk. So they can be sorted into sessions and the game can handle it internally as well.
This is all we know so far. I hope this helps.