Tourney Fields

Several of the European factions can build jousting lists and tourney fields at castles. Each level adds +1 to the experience of knight units recruited there, but the tourney field says "Free Upkeep Units: 1" under its description. What does this mean? For a city, militia units are free upkeep, but what about castles with this structure? I've tried most of the normal castle built units, I've tried knights, and I've even moved some city militia over there. Nothing shows the blue square that the free upkeep units in cities show. Is it not working, is it only units I haven't tried that get free upkeep, or is the upkeep reduction just hidden?

I've noticed this too, and assumed that it was because I hadn't put any militia in the castle .... which you tried.

Maybe its something thats just done (you just get money off a units upkeep), but the nice blue highlighted unit shows you at least which one is being garissoned.

If you look at the Wooden Castle you will find the same problem. It too is supposed to have a free upkeep. But since it vanishes with the Castle, then I just expected it to be a mistake when the files were written. Perhaps a leftover from a time when castles also had a limited 'free upkeep'.

That in turn could explain why players report seeing castles being held lightly. If the AI is observant to upkeep, it is generally going to be very willing to leaves units in cities, however with no free upkeep in castles it will think it is too costly. Further the AI could be geared to assume that a certain level of town/castle has a number of free upkeep units. Thus when it sees that there are three upkeep units in a Castle it will think there are five units in all, which is a fair garrison.