Kudos to doing and citing the research. You are right, every exchange has to conform to NBBO. But some of dark pools don't necessarily keep quotebooks to be coy

Kudos to doing and citing the research. You are right, every exchange has to conform to NBBO. But some of dark pools don't necessarily keep quotebooks to be coy, they instead keep a book of "IOI" (indications of interests). So in an event where a regular trader get a better price at dark pool versus say BATS/INET, their order wouldn't get redirected to dark pool for execution at NBBO. But if a trade does happen between the participants in a dark pool, if a third-party exchange can offer better price then the pool is obligated to redirect to that market to fill at that price. Your second point of RegNMS requiring exchanges to print all their trades. Dark pool report their trades in their own idiosyncratic way. Suppose a large block order went down, I and my counterparty could agree on a VWAP price and just slowly complete our trade over the course of the day or even several days to obscure the order from the market. So reporting might be done, but it might be done as slow and as obscured as possible. And talking about Credit Suisse, CSFB and other banks used to have a suite of VWAP algo's for their customers but they have curiously not updated the algo in the past 4 years. Why not? CSFB's internal trade desk probably is probably constantly developing better algo's but because they want to keep their own customers from having better market obfuscation and be able to front-run; they don't release these tools to their customers.