Well if you launch your own army of satellites and they smash into and destroy someone else's - will you pay? Will you be able to pay? What if it was another government's spy satellite/military Comms/positioning system and you just caused a diplomatic incident? There's a lot of space around earth but crashes aren't rare anymore (see how Iridium has backups already in space to ensure coverage once there's failures/crashes) - add more satellites and the issue gets worse.