Sometimes an empty reply/veiled threat works just fine. I was being probe hounded quite a bit by a certain player. He even sent attacks after I'd probe back to let him know I was online. I always shut down the mines and FRS'd seconds before he'd land, but he didn't take the hint.
I simply let him know that I understood his picking on me (I was significantly lower ranked), and let him know that I had GD options in the area if he wanted to persist.
It seriously does help to actually have a big guy close who could crush him
