Good discussions. I put some of the responses into a train of thought (777 cargo specific):

If you get a Main Cargo Fire warning, you have to take the most conservative action and assume it to be real (even if statistics prove it more likely to be false)

You have no way of knowing whether it is a Li battery fire or not. According to OPs article, "While the fact that a fire might be caused by Lithium batteries does not change most of the recommendations, it can force a situation where the ONLY option is an immediate landing or ditching."

Given two options, fly at FL250 for what could be more than an hour, or descend and prepare to ditch, the conservative pilot would have to assume the worst and prepare to ditch.

Thoughts?