Yeah, reports about gankers reached me before I started playing, which fueled my decision to stick to solo until I know how things roll.
After several hours playing, I now know that in case of an interdiction, the interdicted ship is in a severe disadvantage, no matter how fast you are. Oddly enough, I have encountered some NPC gankers. Interdicted my out of the black (no messages) and started shooting before I knew what was going on. I somehow managed to get away, slightly scorched but generally in one piece.
One thing I noticed with interdictions is that, against NPCs, it is actually best to try to evade the interdiction, as, unless you have a trip of 1000k LS to your destination, you usually won't hear from that interdictor again until after you landed at your destination (given they are still after you).