Account Aggravation

It seems to be all the rage for online banking services to offer ‘Account Aggregation’ these days; a service which allows you to access all your accounts from one, ‘secure’ place on the internet, even if they’re with other institutions.
Nice idea, but the stupid thing is that each bank offering this service specifically forbids you to do it through any other bank, because it means that you’ve had to store your account details somewhere other than your own skull. So, if I have accounts at three different banks and want to make use of this service, I have to violate the conditions of two accounts in order to get any benefit.
I don’t forsee this particular technology fulfilling its promise, do you?