On my last trip on which reasonably in line for an upgrade I was in Bogota for the return leg of my trip, without any access to the internet in my hotel.
Knowing that if didn't do my OLCI at 24-hr mark my chances for battleground upgrade would be virtually nil, I text messaged my wife, who was back in Brooklyn. She OLCI's me exactly at the 24 hr mark. I ended up getting the upgrade. I don't think I woulf have gotten it otherwise.
There are many circumstances where OLCI is not possible, especially on the return leg of a trip. Perhaps CO would contemplate designing a version of the website that would be easier and quicker to use on a pda, so that customers had better access to the process while on the road.