they would have costed land (althrough in some cases they were hired as mercs and paid in cash, eg: the "free companies" in Italy, or the Spanish tercios later during Renaisse). In any event, since land-granting doesn´t get represented inside the game, imho, to "symbolize" those units they should be made them prohibitive (as in: the feudal lord loses the revenues of a significant part of a province, which now go to his knights instead)those types of units are not part of a paid standing army and as such wouldn't have actually cost the ruling monarch anything.
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