Well, 'friendly' - perhaps not. But not hostile, either.
If you had shot them down, dumped them in space and denied the whole event, there would have been no troubles, would there?
Flying around in Kusari space with pilots of lawful affiliation, now that _will_ get you into trouble unless they are Bretonian, or you are KNF/KSP. It is nowhere near discreet, and you will be left alone only as long as you are discreet. You cannot expect a Doshin to allow you to fly along with hostages, and you cannot expect the KSP to go on record and say that Hogosha is allowed to attack the GMG in Kusari/hold GMG pilots hostage in Kusari.
That the GMG hauls fuel to the enemy is a matter that will need to be discussed in the Imperial Council, but until their status changes in KNF/KSP diplomacy, for a 'civilian' to hold them will remain a crime.
John Johnson - Master of Synth.Foods-Convoy|049
Hans Adler - Synth Foods escort wing