Irkalla
ENTP POWWWEEEEEER
I've figured it out, whoward. I'll deploy my solution and return with my results. Suffice it to say that you were wrong, and I was right. HA 
Note that this is with Alhambra in the city, and 4 is the ID of Drill I.
EDIT: Success! It worked.
Here is the code used.


Note that this is with Alhambra in the city, and 4 is the ID of Drill I.
EDIT: Success! It worked.


Here is the code used.
Code:
for promotion in GameInfo.UnitPromotions() do
iPromotion = promotion.ID
if ( pCity:GetFreePromotionCount( iPromotion ) > 0 ) then
pFreeUnit:SetHasPromotion( iPromotion, true )
end
end