So I tried this in the online game. Placed the +Action-token token on the Hireling pile. Had a hireling set aside. But as soon as my turn started (and thus the Hireling comes into play), I didn't get the +Action from the token.
Can someone explain whether this is correct, or a fault in the online version?
The +Action token says you get an action when you play the card. However, Hireling isn't a card you play each turn: you play it once and then it stays in play for the rest of the game and has an effect at the start of your turn. So in fact Hireling was the worst pile to put that token on.