I considered both of those.
But that doesn't work when games have players of varied strengths (RPGs). If its a safe zone, the killer simply has to wait outside it. If they get invincibility, all the killer has to do is follow his victim until that wears off.

That would be futile in RPGs where one player is stronger & faster with a massively higher defense and health...
I just had an idea though: if attacked within a spawn time-limit (and possibly use get_dist() to the spawn site), the attacker's damage is nullified and they are frozen in place for a number of seconds (enough for the victim to escape)

Saucepan Man wrote:

I just had an idea though: if attacked within a spawn time-limit (and possibly use get_dist() to the spawn site), the attacker's damage is nullified and they are frozen in place for a number of seconds (enough for the victim to escape)

Those kinds of solutions are just clunky and unwieldy. They present new problems as well. Just stick to the simple prevention model presented to you. There's no reason why you can't expand it as necessary.
If things are so problematic you could always take bigger measures. Make it impossible to attack in the spawn zone. Make it large and with many possible exits. Make everyone in it invisible and undense (and if you want to do it 'fully', also take care of any possible player interaction inside). You may opt to try and make things normal between fellow just-spawned players, so they can see each other and can't go through each other, in which case the design and implementation is a little different.
If need be, make it impossible to enter the 'spawn zone', only to leave, and if still need be then even make the invisibility-invincibility-non-interactability persist some time after leaving the safe zone. Make those benefits instantly disappear if the recently-spawned-player makes any potentially offensive move (such as attacking someone), of course.

Just note that there's no need to go so far if the game doesn't have large ability limitations between people (such as in a RPG game where characters' prowess highly varies).

More so, if players (or teams) are mostly equal, there's really no unbiased reason in the first place not to have spawncamping as a part of the game. Spawncamping and resisting-spawncamping are skills in themselves, so even with spawncamping you'll have the more skilled player/team winning, meaning spawncamping only adds more options and strategy to the game. Naturally, the game has to be already well-built and balanced for this to work well.

Sorry if you have mentioned this Kaioken, but it could also be a good idea to temp make the player invisible when first leaving the safe zone so the camping killer will not see you flee the area before others can see you again.

If you have set spawn points then just have people spawn invincible for a few seconds and/or until they attack.
However, I think having set spawn points is a bad idea overall. Unless they're inside some sort of fortress that the other team can't readily access (like in TF2 for example)
In HU2 I have a spawn system planned where you become a "ghost" and can freely move around the map, spawning where ever you want after about 10 seconds. We'll see how that goes.

However, your issue here doesn't even seem to be a spawn issue. It seems to be that your game's balance allows high level players to mass rape newbies.

The idea of prevention is only aquired when the perception of value is not added manually.

In other words:

If the high levels aren't interested in doing things at their own level, and would rather PK low levels, then obviously there is something lacking in the game to keep the high level interested in their own activities.

The high levels should be off hunting some powerful item or dealing with high level monsters, they shouldn't even want to be in the low lvl area as it would be completely pointless and lack any personal gain or benefit for them.

I reaffirm this post.

And don't forget me.

UmbrousSoul wrote:

However, if one really wanted to solve PK then they could develop a system that would prevent the higher level player from even considering the lower level as an object of value

Say - remove the EXP gained by PKing them

[link].
Or to put it in another way for you: you could only ensure that players won't consider killing other players worthwhile by employing mind control.
Of course, harsh penalties will deter them, but they still don't ensure anything, neither are they a good solution, for obvious reasons.

Its not a matter of prevention, its a matter of designing around it.

"have a consent system so only consenting individuals could fight" is prevention of a non-consenting individual being in a fight.
As for your already-discussed prior solution, you also used the verb 'prevent' yourself when describing it, but of course, as mentioned, it doesn't work anyway.

The idea of prevention is only aquired [sic] when the perception of value is not added manually.

This is also wrong, for pretty much the same 'obvious reasons' mentioned earlier.