If you seriously believe its worth the banks time bothering to get the information, or you think that bitcoin in some way even registers as a competitor to the banks you are sorely mistaken. The *total* size of the bitcoin economy is something like 1.2b at current count - and the total *traded* amount by the exchanges is less than half that. The banks, even the smaller ones, shift more money around than that every few minutes, hell goldman make more *profit* than that in a month. The fed prints more US dollars than that every week!
Yes, Bitcoin is an interesting thing for normal people to look at, and its ripe for small time day traders and startups to play with, and not to say that maybe in 5 or 10 years time it might be a huge success. But for now, no, its not a 'wet dream' for banks, and is certainly not enough of a market to make it worth them taking any kind of risk. The kind of money they could make would barely offset the cost of the lawyers, and would in no way come close to making it worth them risking their main business.