The aiming of the weapon is sufficient to provoke a response from any normal person.
Lincoln aimed the weapon.
The ships never got within gun range.
And it would not make a difference, if not a single warship showed up. Davis was not going to allow Sumter to be provisioned by any means by anyone. Any attempt to bring provisions to Sumter would have met exactly the same result.
He would reduce the fort by force, before he would let it be provisioned.