The Law of Agency is at play if the broker's you are asking are not officially in a buyer agency agreement with you. Basically if you are asking any agent that you have not signed an agency agreement with, by law works for the seller even if they are not the listing broker. When a buyer speaks to a broker about anything more than the MLS information they must first explain to you the Law of Agency and a good broker will explain the above as well as the specific benefit of enlisting their help as a buyers agent. This agreement has nothing to do with a fee (although there are the rare agents that will ask you to guarantee their commission, but that is a contract and has nothing to do with the Law of Agency.
Once you are clear on the Law of Agency it is always in a buyer's best interest to sign the Buyer's Agency form because once signed a broker (NOT the listing broker - see below) now works for your best interests and they can now research and share every tidbit of information with you.
Keep in mind that if you are asking the listing agent their allegiance is to the seller and they cannot present you with a Buyer's Agency agreement. The listing agent can offer you Disclosed Dual Agency which legally means that both the seller and buyer agree in writing to allow the dual agent to represent them both. The benefit of this is zero to both buyer and seller, in fact the only one who benefits is the broker. When you think about it how can an agent give both buyer and seller proper representation. A good way to think of Dual Agency is that both buyer and seller receive equal representation and that means no representation because it just cannot ever be fair to all parties.
Now if it was the listing broker you asked, I would go to another broker and talk to them about representing you for this one transaction.
If you asked another broker and they told you they couldn't tell you information the only reason would be because you were not offered or would not sign a Buyer's Agency agreement. Even if the brokers work for the same company anyone but the listing agent can help you as a Designated Dual Agent (all brokers in the same firm technically work for the seller until all parties involved sign a Designated Dual Agency agreement at which point the broker working for the buyer has a 100% fiduciary and ethical responsibility to the buyer )
I am certain I probably made it sound very confusing but it can be involved, it is also the #1 reason a broker will be sued for malpractice simply because they either ignored it and got greedy or didn't truly understand the simple complexity of it.
In a nutshell:
All brokers in the MLS work for the seller UNTIL an agency agreement is in place to protect the buyer. That is also why you shouldn't give out too many details to any broker about your interest in any property (especially open houses) until you have signed a Buyer Agency Agreement.
Feel free to reach out if you'd like me to further confuse the situation. lol
(I actually love real estate law which is why I know all this because I have taken every college level class possible)
Here is some info from NAR http://www.realtor.org/field-guides/field-guide-to-agency-disclosure