OK, that's interesting.
So page 52 of the Book of Outcast says "Unless otherwise specified , all fighters with the Sanctioned Fighter or Non-Sanctioned Fighter rule start with a single Wyrd power, either chosen from those included in their gang list or from one of the disciplines presented here"
Looking across the books, Delaque have a specific rule which specifically mentions getting wyrd powers, but other, older psykers (Cult Adepts etc) all seem to benefit from the rule.
What a nuts stealth edit...
On the plus side, it does make Cult Adepts a hell of a lot more viable...