The question is what relationship does the buyers agent have to the buyer. A transaction brokerage which is what most agents work as requires limited confidentiality, a single agent requires full confidentiatlity and no brokerage relationship does not have a confidentiality requirement.
With that said to give the buyer's name to you I would want a clearance from the buyer in writing, and would recommend they do not give that permission. If you want the buyer's name you should have your agent put that requirement up front in the MLS and disclosed to any showing agent and their buyers. I doubt though that you would have many showings and would probably have trouble getting a listing agent.
The problem is with the buyers name, a seller could look their names up on the Internet and find their contact information. Imagine a buyers agent giving his/her buyers names, gives less than complementary feedback on the showing and then has the seller contacting the buyers and picking a fight. Talk about opening up some major issues.
I am not saying you would do this, however it would open up the possiblities. Unless you require the buyers names before showing the home (in writing), I would not be properly representing my buyers if I gave their names to a seller. The only time you should expect to get the name of the buyers is when they make an offer.