Gave this a go myself...

$ ./python
Python 3.4.0a0 (default:57a33af85407, Oct 27 2012, 21:26:30) 
[GCC 4.4.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import socket
>>> socket.getfqdn()
'host.domain.com'
>>> 

$ hostname -f
host.domain.com

$ cat /etc/hosts
127.0.0.1       localhost.localdomain   localhost

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Linux host 3.5.2-x86_64 #1 SMP Wed Aug 15 14:31:07 EDT 2012 x86_64 GNU/Linux

According to strace, both rely on DNS:

recvfrom(3, "Wj\201\200\0\1\0\1\0\5\0\0\00219\003134\003230\003173\7in-a"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("1.2.3.4")}, [16]) = 176

Same behavior on both 2.6 & hg tip.  I think this is a non-issue.