I vote for evil.
FBI Admits It Urged Change Of Apple ID Password For Terrorist’s iPhone
The Apple ID password linked to the iPhone belonging to one of the San Bernardino terrorists was changed soon after the government took possession of the device, Apple, San Bernardino County, and federal officials have acknowledged over the past 48 hours. If that password change hadn’t happened, Apple senior executives said on Friday afternoon, a backup of the information the government was seeking may have been accessible.
The dispute over retrieving the contents from Syed Rizwan Farook’s phone broke into the open earlier this week, part of the government’s investigation into the Dec. 2, 2015, attacks that left 14 dead. Now, the government, through a court order, is demanding Apple build what the company considers a special backdoor way into the phone — an order that Apple is challenging. The government argues Apple would not be creating a backdoor.
So, I'm sure the FBI is saying that the password change was simply meant to prevent other, undesirable people from getting into the phone, and they didn't realize it would prevent this back-up.
Of course, if the back-up had occurred, then the FBI wouldn't need Apple to devise this hack for the iPhone (that Apple is now being asked to produce). The hack is something the FBI has long wanted and will be great for them to spy on everyone, but bad for everyone else.
So really, changing the password can be seen as a ruse for the FBI to support their demand for the iPhone hack, and was done on purpose.
Even more cynically, you could imagine the FBI changed the password, knowing it would prevent the backup, because they were protecting info in the phone that would incriminate them-- assuming the San Bernardino shooting was a govt op. And now the FBI is using this excuse of the phone being locked, to force Apple to create a key to unlock all phones.