I still didn't understand why one needs to prove their ownership when they already set up their email ID in their account?
Unless if they didn't set up email id and ask for support help then they can ask these questions but OP mentioned that he had set up email in his account but still went through this process of proving his ownership.
I had my two factor authentication enabled and still i was not able to prove my account the first time around as they promised to follow up with the details in my mail ID and i did not get any mail from them and after a couple of days i had to contact them again and verify the details once again, i was not active in the site for a while and so it was hard to find my old transaction details and IP address i was using a year back , but luckily i found them from my old hard disk, if not for those transactions and logs i do not think i would have got my account back.
If you enabled your 2fa then no need to lock your account right? Because they know that it is not so easy to hack 2fa enabled accounts.
But anyway they also got a valid reason for the security of user accounts so they may be doing all this hard work. Because it also adds more workload on their support team to help each and every user whos accounts are locked.
Even if 2FA is enabled the accounts can still get locked due to repeated failed login attempts.
Lately if you go to the Cryptopia thread many are getting their accounts temp locked due to too many hackers trying to login. And we all use 2FA on that site.
Basically if you keep any large BTC you should have a unique email, unique username and unique password to avoid this from causing annoyances.