The only problem I have with an alias is that GI is also used for general infantry and "gi" can also stand for general issue, both of which are terms that might be tagged in a military-themed image.
Posted under General
I don't see either of those as a serious obstacle to an alias here; G.I. doesn't mean 'general infantry' and there is no compelling reason to ever tag 'general issue' (or 'government issue') or 'galvanized iron', the two expansions of G.I. that I've heard of.
We try to avoid the _(artist) qualifier due to ambiguity concerns, so I went with gi_(46rain).
Aliased gi to dougi and made wiki comment.
And agree that the military "G.I." abbreviation is not something we would tag here.