OK,let me speak from PERSONAL g1 experience.
I joined g1 on turn 24. (For g2 players, all new players in g1 started in
the same place, the Imperial City.) I messed around doing the standard
newbie things, applied to the Sheriff for permission to enter his city and
got it, went in the other direction to get Beastmastery, contracted with an
AOO noble to get transportation to the Cloud City to get Weather Magic,
built a ship, etc.
On ~turn 32, about half my nobles entered my ship to make a short trip and
do a bit of fishing. In the province IMMEDIATELY ADJACENT to the Imperial
City, the province where all newbies started, my ship was ambushed by
Swishbuckler and Rory Patch, two known AOO nobles. I had a few pikemen and
a few hundred coins on me...nothing to justify such an attack. The pair
had evidently found a hidden island in that province, and were using it as
a base from which to routinely issue hostile orders against ships seen in
the safe haven. The province contained several abandoned ships, presumably
from others of their victims.
A friend whom I had persuaded to join the game also had several nobles
captured around turn 45 by known AOO nobles, six or seven provinces west of
the Imperial City, again with no provocation whatsoever.
Neither of us had made any political ties, and there weren't any wars
going on at the time. It was rank newbie harvesting, pure and simple. If
anyone disputes this I still have the turn reports. This sort of thing is
why the AOO made so many enemies.
No one is saying that all AOO nobles routinely attacked newbies. There is
a decent body of evidence, though, that they took no effort to stop members
of their alliance who indulged in such activities.
PS The good thing about my capture was that I was rescued by the group who
subsequently became my current allies. I came back and eventually helped
the Gauls get in a few licks against the AOO south of Atnos, before my main
nobles had the bad luck to be passing through the capital Gaulish city on
the same turn it got flattened by an AOO strike force.