Not all of the 250 crew of a Fenris would be hardened space veterans that can sum up critical situations in a split second, willingly throw themselves on their sword, or deftly wield a deadly weapon. If a bunch of civillians manages to take hostage the senior officers, then the rest of the crew would be more likely to stand down peacefully. There would be some willing to fight back, but there would still be a desire to preserve their own lives and the lives of those around them.
On the other hand, if a ship was to be invaded with the intent of taking military equipment, wouldn't the civilians forfeit their "protected" status and be labelled as criminals? Meaning they'd be subject to whatever laws are necessary to curtail criminal behaviour. Basically the same thing as mikhael said.
To the initial question on blockading a node, it would depend on how smart the hijackers were. If they think in 3D, they'd possibly position their ships in an 8-pointed diamond formation, with extra ships then filling in the diagonals between, other large gaps, then positioned behind the initial grouping of ships. Given enough ships, it would become a multi-layered globe.
A ship enters and leaves subspace by essentially vibrating on a molecular level, allowing the ship to slip through the proverbial fabric of space. Now, to determine what happens next, we need to know how "solid" a ship is when it enters/leaves subspace - can a ship be shot at and be physically hit while it passes through the barrier? If not, then it would probably turn out that any object sitting in the exit point would interfere with the coalescing, becoming a big mass of combined atoms and molecules. If on the other hand the ship does have a solid pre-cohesion, it would displace anything pre-existing in normal space. Or, depending on the pre-existing energy states, the incoming object would find itself with nowhere to go and disintegrate.
Sound reasonable?
