Spawn camping has been an annoyance since day one and can happen in any game where two sides collide and skill, numbers and class balance factor in.
Spawn camped scenerios are unenjoyable for both sides. People being pinned in feel frustrated because they have no room to move out in a lot of cases. Your forced to go forward into a gauntlet of positioned opposition.
People doing the spawn camping have generally boring time too. Some groups try to hang back more but unless you have communication and influence over the second group, your risk them getting run over if you pull back. If you stay up with them, you risk them pulling guards and wiping a bunch of your force.
I have in the past posted up discussion threads on ways spawn camping could be reduced by minor or major changes to scenerio layout, mechanics etc..
At this point in time, I think most development is being spent (properly) on the new rvr pack and major patch changes. Existing scenerios will probably not be changed to accomodate complicated ideas and scenerio redesigns such as auras around the warcamp that up damage/healing or alternate exists/portals.
A simple way to aid in reducing spawn camping in existing scenerios that would -hopefully- involve little to no coding would be to increase the damage on the camp seige weaponry by large amount. Maybe even have this player controlled seige weaponry kill people in a single shot if they are silly enough to go into range of a warcamp/spawn location and get hit by the weapon.
People would quickly learn and adapt to the new range and more breathing room outside of your spawn area would be allowed. You would also be more in control of clearing the campers out, instead of pinning your hopes on unreliable guards which seem at times to do nothing at all.
Obviously this does not solve the root causes of spawn camping, nor is it meant to. This is simply an idea for a quick fix to give more breathing room outside of a spawn location in a scenerio and move the fight more to the middle of the scenerio. In the same swipe, it should help remove NPCs from being a factor in scenerios.