It probably has left an entry to gconf or there is another application which adds networks without name. If you are interested you could could run this and look, if you can identify it:
~ $ gconftool-2 -a /system/osso/connectivity/IAP/3de3d8eb-5171-4e52-9b56-ad3a42997f3e ipv4_autodns = true ipv4_type = AUTO type = GPRS ask_password = false gprs_password = sim_imsi = xxxxxxxxxxxxxxx gprs_username = gprs_accesspointname = ~ $