Almost no one on this site is qualified to advise OP what is and is not appropriate to disclose about a bank's operation. It is very obvious why banks do not want to share specific information about their business (Ever notice that tellers sometimes will not tell you how many rolls of coin they have until you tell them you want up to $2k worth? Ever notice that tellers will sometimes be very hesitant to tell you what time the coin order is delivered by the carrier?).
While some banks are more lax than others, you can bet that there are official rules about sharing any information. While a casual breach of those rules might not warrant formal correction, a blatant and widespread one likely would. My advice would be that the discussion should focus on good customer etiquette and should avoid any sort of bank-insider type questions.
Good Questions:
1) What day of week (and time) should I bring big dumps so-as to not interfere with tellers serving other customers?
2) Do you mind if I call ahead asking if you have certain coins?
3) Should I bring coin rolled or loose?
Suspect Questions:
1) What day of week (or time) does Brinks come to the bank?
2) How much coin do you keep in the vault?
3) How many tellers are there in the bank around closing time?
