iPad4 running iOS 6.1.
It responds to bonjour/mdns requests under its current name (eg ping example.local).
Go to Settings > General > About > Name and change name (eg to newname).
iPad stops responding to mdns requests. Wireshark shows no response from the ipad.
Reboot/reset network and all settings has no effect. Under Xcode, console shows:
mDNSResponder[31] : User updated Computer Name from “example” to “newname” mDNSResponder[31] : User updated Local Hostname from “example” to “newname”
The iPad shows up as "newname" under iTunes and XCode, so the device's friendly name is OK. It also sends out mdns requests (eg browsing for http://somewhere.local).