IA protects the right to recruit the unit type you want, meaning: Infantry, Archers, Cavalry, Mixed Infantry, Special Forces. You get to pick whichever you want, no one can tell you otherwise.
Discussing IA gets into territory that is often undesirable, but it is fairly clear that players can be ordered how many men they must have. Not building or destroying certain recruitment centers is allowed as well. Anyway, how it applies to paraphernalia is...well, it doesn't appear to even be covered, interestingly enough.
For the most part it's common sense that if you have no unit, every paraphernalia except scouts and caravans would be useless. Maybe demolition tools might work. But banners, carts, and siege engines can't even be used without a unit. Healers, however, can, but they do nothing without any wounded men except eat gold. So I find it quite ironic that the one paraphernalia that is in a potentially ambiguous area not limited by mechanics and not actually useful without a unit would lead to a question about whether players have the right to choose what paraphernalia they can have.