No PvP until level 5 - Todd confirms in interview

From the same article that mentioned fast travel (https://multiplayer.it/articoli/todd-howard-fallout-76-the-elder-scrolls-6-starfield.html) - "Per esempio al momento non puoi uccidere un giocatore finché non raggiunge il livello 5"

Although it could well change at this point, it seems as though one player will not be able to be killed by another until they reach level 5. Might make for a bit of a safe zone in the earlier areas.