@Hygro:
Just for the record, Worker Dogpiling is the act of adding a worker to a city that can not support it with food, causing it to starve at the end of the turn. The next turn another worker is added to the city (so it yet again is one size larger than it can support food-wise), ad infinitum. This gives the city a permanent size bigger than it's food can support, therefore enabling wonder production that little bit quicker. Since only one worker will die each turn from starvation, all tiles can be maximised for production, and you can make the city size 21, and only have to add one worker per turn.
Tassadar (as far as I can tell), was just talking about adding a worker to a city to poprush something. This is allowed in the Tournament, unless I am mistaken.
I know you weren't explicity talking about Worker Dogpiling, but that is the only exploit I can think of that is related to adding workers to a city.