marine reinforcement in enemy territory

[metabagel]

I noticed that marines can be reinforced when surrounded in enemy territory and without access to any towns or cities. This happened in the vicinity of New Orleans. N.O. had not been captured. There were no sources of supply other than the coast, which seems to be where marines draw their supply from. I was able to reinforce marines from strength of 2 to strength 10 in a single step. This doesn't feel right to me.

[Beriand]

They do not draw supply from coast, just have some stockpiles after landing. Their initial supply drops by 2 each turn, so if they land at 10, the next turn they have 8, then 6 etc., 0 after 5 turns if nothing is conquered.