You, the bank regulating scientists, would you please explain something to a layman?

Below what I saw while walking around in the Washington Zoo with my constituency (my grandchild) and which inspired me to ask our bank regulation scientists friends a question.

Smithsonian scientists learn a lot by observing animals. 

Now its your turn to WATCH AND LEARN

So now it is with you bank regulator. You are the scientist. Scientist learns a lot, by observing banks and bankers. So please explain.

Observe what type of bank exposures have caused all major bank crises:

1. One or many of those ex ante considered risky, and that ex-post turned out to be risky?

2. One or many of those ex ante considered risky, and that ex-post turned out to be safe?

3. One or many of those ex ante considered absolutely safe risky, and that ex-post turned out to be safe?

4. One or many of those ex ante considered absolutely safe risky and that ex-post turned out to be very risky?

And now, you bank scientists answer us non bank scientists. 

For what type of exposures would the empirical evidence suggest the capital requirements for banks should be higher?

Aha! 

And so then explain to us, in easy terms, why you, the Basel Committee for Banking Supervision, the Supreme Global Bank Supervisor, set rules which allowed the banks to have much much less capital for what was ex ante perceived as "absolutely safe", than for what ex ante is perceived as risky?

Please?

PS. My own humble opinion is that our bank regulation scientist friends have got themselves trapped in quite a bit of confusion. They keep on analyzing the possible failure of bank borrowers and not, as they should, the reasons for why banks fail, as entities or in allocating credit to the real economy. And that is of course not the same thing, or, as they say in French, c’est pas la même chose… For instance instead of looking at the ex ante credit ratings of bank borrowers they should look at what bankers do when they see those same credit ratings.

In other words, the regulators instead of analyzing so much the ex ante creditworthiness of bank borrowers, to determine their risk weights, should have analyzed, at least a little, the ex-post explanations for why banks fail and for why bank crises occur. Holy moly!

PS. As I see it: The world (with its banks) is much better off thinking that the risky are less risky than we think them to be, than that the "safe" are as safe as we think.