Given the second to last page, I'm guessing somebody's going to just recognize one of them on the way in or out eventually. This plan seems kind of weak- it just says that it's unlikely that somebody we'll recognize them on the way in, that it's unlikely that anybody in debt to Teiai would be on the second floor of the bank, but given anxious the debtors are for the money, they'll probably call Teiai after seeing someone for just a second. There are also probably people crazy enough to camp outside banks to find Kaiji and friends (as well as Teiai people), and the bank tellers will eventually learn about the Teiai bounty. I imagine that this chapter's just building up to something bad for Kaiji and friends.