There was a nice article on either kniferights.org or atki.org.
It covered the "general" legalities of a knife and made a strong point that an individual should be sure to look up the state and local codes as well.
However, it said in there while having a knife such as a switch blade as a 'curio' on display in your home is acceptable. It's not ok to take it in your pocket or car and carry it around with you.
That being said, I'm sure any DA could argue that a sword is a blade over 4" and therefore illegal to carry.
None of us know the actual details of the situation you were on the jury for. So in that end we can only speculate.