The Sunshine Card is the justification for the lower-than-average pay and per diem paid at certain plants, mostly located in warm, sunny parts of the country, despite the higher-than-average cost of living in that area.
"Everybody wants to work here because of the sunshine, the beach, ... etc., so why should we pay more?"
There are more trump cards in the deck. There is the Long Outage (or SGRP) Card, where people are lured into low-paying gigs because they expect to work a lot of hours at one place. There is the Off Season Card, where they can pay less because their outage is scheduled in December or January, when there is less work available. San Onofre combines that one with the Sunshine Card to get a steep discount. And I'm sure that there are a few others