Before PvP, one should always alarm a DM and, in case it's a NPC crowded area, should also wait for approval.

Does this rule apply for a member of the Watch/Spell Guard? It brings up the following two issues:

Can the PC who's chased respond to the assault in front of NPC guards?

If one decides to resist arrest, should he inform a DM? Or can he just run away and respond to possible PvP while near NPCs (when it can't be prevented to best of your abilities, of course.)

Watch etc should always get DM permission, however they obviously get a -lot- more leeway when it comes to NPC's in Upper Sanctuary.

The attacked played can obviously respond and defend themselves with common sense always in mind - beating down on a Spellguard that was unlucky in their stalking for 10 minutes while NPC's watch might be silly, whereas running past unwary random privates is absolutely fine, even uninvisible.

I'm sure you knew the answer to this question anyway though man, tell someone on IRC what the question's in relation to exactly and why and they'll probably be able to be more specific :)