This is a rather long post. You have been warned =)
This is that I think of steal killing in Highhold. If a tank or warriors
starts attacking the mob, then I don't think its wrong to blast it, IF you
start blasting when hes just started on the mob. This is for a very simple
reason, if all the mob he attacks is gonna by his, he will get everything,
especially those in groups, where there are clerics in it. Since there is
practically no downtime. Anyways, if you start blasting it, the mob will run
over to you and attack you, so if anybody else starts shooting at it, they
are just helping you to get kill. I have seen orc fanatics that have spawned
and die in 1 sec after, becos 6-7 casters shoot at it at the same time.
Usually the player who does the most damage with one spell , usually the
magician or the wizard would get branded a stealer just because he is a
loner and has no group. Of course those assholes which are really out to
steal kill can be seen very obviously, like what ziltus has mentioned,
waiting for tank to do 20-30% damage before shooting. However, In my opinion
if i shoot a mob when you are just starting on it and I kill it after he
beats on me, although a tank type or some other caster shoots at it, I don't
really care if you brand me a kill stealer. If I spend 30% of my mana on a
mob instead of 80%, its not because I want to, but rather its because other
caster are trying to blast my mob, so that they can get kill and when they
don't get it, they get pissed and call you names again. Thats why its very
important to get a group, since you have your own tankers tanking and you
nuking. As for named NPC, its FFA but when you do get the kill ppl will
curse and swear saying they waited 20 hrs for the named NPC. Well, If you
can't get the kill yourself, get a damn caster who can nuke for you. I'm
sick of ppl whining cos they can't get kills especially when I shoot at the
named one and even when he comes to me, the other tanks from other groups
continue to beat at him and expect to get kill. I myself have always grouped
from level 16 to my current level, and there was only once when I tried to
do solo and do what other wizards did. I must admit xp came in very fast, at
a rate of 1 bubble per hr so I could level in a day. But the only group was
there got pissed and one guy even wanted to duel me, a level 21 ranger. Of
course I just ignored him and did almost 3 bubbles of xp that day. One funny
thing later was how his group ran and zone leaving him alone fighting 2 orc
scouts. Seeing he was about to lose, I became visible (I am invis when
medding) and he asked for help. Of course I helped him out, but he still
called me names later on. However that was the only time I soloed like that
and of course it was very lonely not to mention getting tells on "Thats not
very nice. But I don't think you care anyways" Well, hes right on I don't
care. I once heard of a guy in Nektulos forest saying "If I can train a
skeleton on you. Then its your problem". If that is one guy attitude, there
must be many others who have this type of attitude too.THat happened when I
was in Prexus server playing my necro. I myself have kenna like that, I sit
on floor medding and suddenly 2 skeletons jump on me. I was like level 6-7
and that meant instant death. Of course the skeletons were not spawned on me
but rather trained on me. Since many people have this type of attitude, I
don't see why I must care what people say. This is what I think, if a player
steals your kills and asks for help later, by all means let him die since he
deserves it.
As for reputation, high level wizards are often invited into groups more
often than not. Since you can't make EVERYONE your friend anyways, although
its always better to have more friends than enemies. I think most people
don't really care if you have an experience on stealing kill or not. This is
so because if you steal kill FROM them they won't like you. But if you steal
kill FOR them, they will all praise you and even want to group with you more
because they know who can get the xp and who can't. However on Loot stealing
I have seen ppl being shunt before because they loot a named NPC and run
off, ignoring their OWN group members. Loot stealing is absolutely lame, if
you don't wanna share your loot, DON'T GROUP and DON'T whine if you can't
get the kill. If you want to steal kill, go make a wizard or magician or
druid and see how hard it is to get your XP, especially at the lower levels.
I have seen a druid which purposely did 50% of damage and let tanks finish
it off, so that he could get the xp, and he was soloing. Another time at
gnolls, my friend received tells from another group on how he can't get the
kill on the named NPC because that guy had a druid friend which he claimed
could outblast him. So my friend ask me to help him get the kill and we did
get the named NPC. Of course this resulted in the other group being
extremely unhappy and cursed at us. However in the end we still got what we
wanted and the other group with nothing.
Just my 2cents worth of opinions.

Leshrec Kalesk'Thor, High Elf Wizard of the 6 Sixth Circle.
Innoruuk Server