I recently had my MacBook Pro repaired at a Genius Bar. I must say it was an excellent experience bar one big big worry: on leaving the device for repair, I was asked for my username and password so Apple could check everything was working after the repair. I provided them, but that night I didn’t sleep a wink. The username and password give access to all my contacts and keychain - my life’s work and finances could be stolen in a flash.
I returned to the store to change the password. After the repair, the agent called to ask again for the password. I declined and told him to use the guest account instead.
Surely this must be against Apple’s security policy? I can’t believe after all the brouhaha with iPhone security that it would even expect this.