A shopping centre will get about 4 or 5 APs for pay-as-you-go Internet access.
H-REAP was suggested however I noticed in,
Enterprise Mobility 4.1 Design Guide
under "Restricting Inter-Client Communication" that,
"Two or more clients, associated to a WLAN that is locally switched (by an H-REAP), are not prevented from communicating with one another even if Peer-to-Peer Blocking mode is enabled on the WLC. This is because locally switched wireless traffic does not go through the WLC.
Those H-REAP WLANs that are central switched have inter-client communication restricted based on the Peer-to-Peer Blocking mode setting on the WLC."
Since Central Switch which supports Peer-to-Peer Blocking would probably give crap latency, that probably rules out H-REAP for this applications.
As far as I intrepret document says only about communication of clients within the same WLAN in central and local modes. This is no way conecerned about the latency of internet connection. Latency depends on the bandwidht you subscribe.
I am curious about why you wanted to block peer-to peer connections. Since that doesn't refer to the kind of peer-to-peer file sharing that a lot of users want to block (Bit Torrent, Limewire, etc), maybe you misunderstood this and the blocking isn't really all that important in this environment.
I'd think that in a shopping center where the hotspot users are going to be transient, there would be little opportunity for anyone to even want to do the kind of peer to peer connections that this is designed to stop.
Just a thought and please don't take offense if you knew this already!