They choose PVP every time they shapechange
I have a great story, about this when I transitioned into an interesting thing from the new Fist tower in the woods of sharp teeth.
Today I saw a giant golem carrying a female wizard near the newly built trade-way ruins near the new tower the fist have put up ((thanks new Map editor guy)) and he was being attacked by bandits. So I fought the bandits on Zorn with horrible punching accuracy, and he placed the female wizard down. He transformed back into his normal form, a wizard, and watched me slowly defeat the bandit. I then turned around asking
"Say, where did you come from?"
And he said something along the sorts of " I'm sorry, but I cannot let you live for what you have just seen. Any last requests? "
I had not seen him transform back IC and suspected this wizard was not the golem (when it obviously was). IC, however, Zorn did not realize any of this, and was completely confused why he would tell Zorn he wasO about to die for seeing so much.
I then asked him if he was a Bhaalite for threatening me without a real purpose.. I think he said he served Kossuth in his own design, and then I said "Well, guess it's time for me to book it. Best of luck to me! See you! " I then proceeded to run, but he hostiled me and Greater Ruined Zorn's rear end (Zorn currently only has 82 HP).
For some, this sort of PvP without auto-consent would drive a person mad, but for me, I found it perfectly legitment and was quite happy with it. Reasons:
a) The wizard supposeldy thought I saw him attack / murder this other female wizard ((assumign he did so, as I didnt see it OOC or IC at all ))
b) The last request was fair enough warning and game that PvP was about to happen.
c) I fully support PvP and do not complain about it if it happens. Level's do not matter when you play in a roleplay server. For example: I had an old Stormlord whom went around trolling people and starting fights. He was once four-shotted by a half-orcish paladins who only used his fists. Did this anger me? Did I cower out? Did I complain. No. No. No. Backing out of PvP because the person is level 30 and your level 1, is like metagaming in my eyes. How do you know this poor looking scrub-of a guy is level 30, when your level one nobleman looks much more richer than him? Die playerscry!
If people run around killing without a real reason, without a roleplay warning, without some sort of motive, then it is wrong. But any PvP where the person clearly speaks, mentions anything, or states something is perfeclty game. If you come up to me and yell "I'm a serial killer! You're about to die!" Then give me a chance to respond, then I have no grudge with you, as you have clearly given me a chance to react in a certain way.
But not everyone enjoys this, obviously. And people complain about the game mechanics, and all that and take it into /tell and whine.. blah blah, waste my night of roleplay.
Suck it up, move on. Anyone who takes up a weapon or deadly magic that can assault and kill someone has a high chance of PvP.
ERR... I completely ranted towards the end in the paragraphs above, forgetting the entire topic.
Transitions are indeed a game mechanic...but I think if someone is shapeshifted and transitions into another area, then I personally still think it should be fair game to PvP. Perhaps not Killable on sight, but with a good roleplay in the mix first. (( I don't support KoS whatsoever. A good epic dialogue is always needed, espicially if the character is a dark and evil necromancer. Mwajhahahahahahaha!!!!)) A person should be given a chance to response. A nightwalker changing back into a humanoid form should still be killable though (WITH DIALOGUE). Transforming into undead or evil creatures like devils, is just evil outright.
Or you could be evil characters, like I usually am, and disregard all the shapeshifters, when you yourself may be one :p
Just my thoughts on this heated topic.