Cautios nature gives +3 PE if you have an option ''do you want to encounter: Vedaras Own'' message. If it doesn't appear, you don't get your +3 PE.
Nobody is going to take this perk as long as you can fill your slots with best pvp-related perks.
Yeah perks like Quick Pockets and Faster Healing or Earlier Sequence or Pyromaniac should be possible to pick at every 5th level where you can pick only these crappy perks!