I don't think a bank will want to go down the line of arguing the contract shouldn't be binding because they shouldn't have to read the small print - that sounds like an overall loss for the bank in general.
That's like I would initiate a contract with you and after we read it together and you agree it's what you want to sign I covertly slip a page into the pack that completely changes the terms and trick you into signing it without you actually knowing it's there. You can reasonably claim you intended to sign the original one, not the one I secretly modified - and I expect the court be more sympathetic to you than to my claims "you should have watched my hands all the time!" Of course, it'd require you proving that I did this, but if you can, your case sounds pretty strong to me.
Doesn't this case show that they cannot reasonably expect the contract to be identical to what they sent, in respect to all future contracts?
1 - The bank signed a copy then gave one to the customer to sign. If the customer changed the print at this point, it would no longer be valid.
2 - What this guy did, the bank gave him a copy, he modified it, then signed it, then sent it back, to which the bank approved. Which is still technically valid.
Your contact probably has aterm about them being allowed to change the contact and probably not even notifying you.