Apple claims that if you use find my iphone activation code, the current user's apple id and password will be required before anyone can activate and use the devise. Does it work??

Yes it works, if Find My iPhone was activated before the lost.

There is no activation code, it uses your Apple ID & password and when you switch FMiP on it will automatically activate.

Luabi wrote:

TThanks Ckuan,

but you didn't quite answer the second part of my concern: can hackers still manage to break into iCloud and compromise the activation lock without my password?

Curiously, even though the phone has since been offline, I just found today that the serial number and IMEI number of my registered iPhone 6 has been changed!

So, my question is, how truly secure is the iPhone activation lock service if hackers can so easily bypass it?

By the way, I have lost two iPhone 6 and one iPhone 5 to pickpockets and car thieves in the last one month!

No, if it is then you will hear it all over the news. Imagine 48 millions iPhones are added in a quarter (3 months in a year).

Most hackers use social engineering to trick users for their passwords. and some of the passwords are too simple to be effective.

Note if you have 6 digits passcode as well as an Apple ID password with 2 phase authentication, you are very safe.

Just do not let phishing / scam tricks you. Never give your password to anyone online or to "friends".