The law says "concealed on or about your person"
There is no clarification as to what that means that I am aware of. Technically I am pretty sure that a unlocked case would be no different than a fanny pack or a back pack and that it would be considered concealed.
A locked case probably could be considered not accessible and you would probably be ok but the law is vague enough that even that could be a problem.
A friend of mine had his nephew charged for a gun that was in the bottom of a gym bag in the rear floorboard of his SUV while he was driving and no one was in the car. There was no way for him to get the gun without stopping and crawling into the back or opening the door from the outside but he still got charged.
Technically the law is vague enough that as soon as you took possession of a unlocked cased gun, you could be charged, even in a gun shop. I dont actually think it would happen but the law certainly is vague enough.