Interesting thread.
First off, cover it and put an airlock in it, as it WILL ferment.
This could be a tough situation, because you are taking a chance by adding MORE priming sugar when you do get a chance to bottle. Bottle bombs are likely cause you have no idea how much of that sugar was eaten by the yeasts.
Personally, I don't know what I'd do here. Let it ferment out all the way and prime again? Or take my chances and just bottle it up without adding anything else? I don't know.
Anyone else?