Lockdown Lock Out
Locking any phone to one network is plain daft, they must have hoped that the 'partner' would help launch the beast.
It is one thing to get a phone heavily subsidised so it appears 'free' and is thus locked down. It is anther to only have one choice, from that point on you tend only to look for reasons not to go further and from reports it appears there were a few of those. Or was it more than a few reasons?