Re: Charleston Under Arms..
It looks that way in the writing David posted. Perhaps it was the added presence of the Federal forces, as David said, that brought on the later actions. They were viewed as a threat and they were intended to be.
Here you have states who condemn the South for having slaves but will not accept them if freed. The planters needed workers to get the crops grown and harvested. Those particular crops didn't grow so well in Northern climates but were a valuable commodity on the world market. Had the planters freed the slaves, where would they have gone? A few could have made a living with the skills they learned such as smithing and such but most were uneducated and had no means to support themselves or their family. Without the government giving them those acres and the mule that came later, what would the consequences have been? We can only speculate but I don't think it would have been a simple matter.
I believe the Confederate militia's took over the aresnals in their respective states because they believed they were for their use. With the buil up of forces at Moultrie/Sumter and Pickens it made sense to be watchful. Lincoln got that ball rolling and it didn't stop until the last shot was fired.