This deserves more attention. I encourage anybody with enough spare time to work a poll at least once (they typically pay you and cover commute costs).
Usually the people training volunteers were never properly trained themselves and, in my experience, responsibilities are delegated emphasizing fairness over merit.
The last poll I worked at had volunteers check in voters using some clunky software on an old laptop. It quickly became clear that none of the volunteers used (or perhaps even owned) a computer and, as a result, check-in was a disaster. I offered to take over or re-train them on how to use the software, but no -- it was my turn to hand out "I Voted!" stickers and I had to wait my turn to work the check-in station.