That's not true. BIND is a DNS-only server. It never checks a hosts file. Most resolvers (the part of the OS's IP stack that resolves hostnames, etc.) will check the hosts file first, but this is almost always configurable, usually by the /etc/nsswitch.conf file. To confuse matters a little more, many resolvers are based at least partially on BIND code, and are sometimes referred to as BIND resolvers.