By that logic if a mage wanted to hide it's true nature it would have to lug around a giant 2 handed sword and plate armour, which I doubt it would have the strength to do being a true mage. Cloaks however, given the time period of the game would also be worn often by travelers, I assume. No sane wizard that has played a 1000 rpg's would wear a cloak I'll agree.
The easiest way to disguise a wizard or other caster in a party (a trick I have pulled in dungeons and dragons occasionally) is to dress like a civilian. That way the initial threat assessment will likely pass over you for other targets that seem armed and dangerous.
Not that it would ever work for this game clearly, that would be an awful lot of code to try to determine disguises etc for little real pay-off honestly.
I just wanted to share my opinion on how to be a discreet caster. Cloaks that are very basic fur cloaks or brown/green and undecorated with civilian clothing could work, but they would restrict your somatic components to spells I would think, so that would probably be a reason not to wear one if not needed.
