Even if a client demanded and was willing to pay for the diverse paths there can be none available.
When there is demand for something that the market cannot supply due to political constraints, then there are political solutions.
The number of paths varies widely between cities, and has little to do with demand in those cities for diversity or how critical they might be to the nation as a whole.
If requirements for network path separacy can be communicated in such a way that people clearly see that it is critical to the nation (or any other political body) then it is possible to release additional path opportunities to the market. The rules of thumb that I suggested had to do with how much network redundancy is likely to be "enough network redundancy". I also didn't supply the numbers to back up these rules because, to the best of my knowledge, nobody has studied the risks involved in enough detail to do analyse this. I did receive one anecdotal account related to the ice storm in Montreal back in '98, I believe. It seems that this city of over 1 million inhabitants had 5 paths providing electricity to the city and 4 of those paths were knocked out. Interestingly, nobody suggested my numbers were too low or too high. I suppose that is a rough and ready tacit approval of my rough and ready rules of thumb. --Michael Dillon P.S. Let's hope that Jay gets his Mediawiki off the ground so that we can develop other "best practice" rules in a format that makes it easy to use them for training new people coming into the industry.