Of all the things that determine the outcome of a PK engagement:

Player skill, preps, game knowledge of terrain/skills/spells/races/classes/cabal powers/tat powers/form skills and vulns/duration and effects of mals, etc., etc...

...the easiest and fastest for a newbie to acquire is preps. Taking them away is not going to allow them to go around PKing vets.

Also, the scenario you describe where they accidentally become enemies with every cabal is still going to get them beat down and the prep idea will have 0 affect on that.

Finally, "vets" do more to help newbies than any other group in the game. Mostly because 1)we're online 2)we have the knowledge they need 3)most of us appreciate new players, know how they feel and get no pleasure from PKing them into the dirt. 3)We're not IMMs, so we can help them individually depending on what they need.