If you don't have ITA and want to chance it, you can go right ahead and try linking accounts. But I won't advise anyone to do it after ITA.
My long story:
I used my banking info as sign-in partner to create my profile in April 2015. Everything was fine until some time late August when the bank issued an unauthorised transaction on my account. I noticed and immediately brought it to their attention. They then had to cancel my access card...
This now meant I have zero access to my CIC profile!!
Unsure what to do, I created a new GC Key and read through it. It gave an option to link accounts. I tried and tried with no luck. I then had to email CIC for technical assistance linking the accounts. They responded on Sept 8th with a screen shot of the information as I should enter it (which I was doing all along). Turns out, when I linked my account, I got ITA the same day.
Imagine my excitement!
All the excitement was short lived, as the application did NOT come over!!! Remember I have no access to the original account because of the bank error.
I called twice for assistance and was told to email for technical assistance (AGAIN).
I did so, and guess what? I received one email advising it is being looked into. Well my ITA
AND my profile EXPIRED!!! It took THAT long. I still to this day have not received a follow up, although I followed up (which might I add is a tedious task in itself).
I then had to create another profile and do the waiting thing all over again from November 2015. I just got ITA Jan 13th.
Here is why I said don't do it... But that's just me speaking from experience.