Transporting civilian supplies is always much better than transporting military supplies.
Transporting military supplies would largely confirm the notion of joining a war, after all, everyone understands that supplying weapons is supporting the fight.
But transporting civilian supplies sounds much better and hardly solidifies the notion of joining the war.
Of course, everything is just talk—transporting an excessive amount of supplies while hiding something is normal; as long as there is trade, it can be a point of attack.
However, in this world, anything political cannot avoid being attacked.
The key lies in whether it's really done or not. If it's truly done, any hidden acts can become a weapon to break public trust in the government, even the most arrogant politician will consider such impact...
Crossing the boundary of arrogance leads to stupidity: only a foolish politician would deceitfully and carelessly conceal.