Yes, that's how I understood the term too - sneaking in to loot
someone else's loot just after the timer goes.

Quite right. If it's offered up for grabs in an OOC, he who gets there
firstest...

Palindrome

Although there are particular situations, like raids, where that holds
up, when I see some a.shole (read: bard) killing everything in the
zone, and just leaving it because he's so friggin greedy that he's
afraid someone else may actually get one of the mobs, I feel free to
loot anything that the timer has expired on, and I, nor would a GM,
don't consider that ninja looting by any stretch of the imagination.
Just because you <can> kill everything in the zone with absolutely no
regard for other players doesn't mean you <should> or that it's right
to. Generally speaking, I've found that when you start stripping their
kills, they tend to slow it up and actually share with other people
once they realize that they're wasting time. If you or a member of
your party can't find two seconds to loot a kill someplace in the next
two minutes because you're busy, then you're out of luck. Two minutes
is a long time. Example: I go into Karnors all the time and find
upwards of ten or fifteen dead drolvargs near the entrance--and not a
person in sight. Five minutes later, some people come up from below
and start looting the crap. That's fine, but don't be surprised if all
you find is plague mites. I don't ask permission to loot a corpse with
a minute left of the expiration timer, that's for sure. "Looting a mob
that isn't yours" is horrifically vague, because after it's dead for
two minutes, as per the game rules, it's not yours anymore, it's
public property. As in the OP's situation here, it was announced that
it was rotting. At that point, it's first come, first served, period,
and any regard for someone calling dibs on it is a mere courtesy.
Like I said though, on a raid or with prime mobs dropping things that
need to be rolled up, it's a different story.
I've always understood the act to most often be the prick in the group
that no one knows, jumping in and looting an item, then dropping out
of the group and leaving, or logging, which, as I understand it, at
least at one time, would bring retribution from a GM if you did it.