Wasn't that the case with some bank's (AIB's?) personal banking system in the past but they fixed this "node locking" problem since?
Don't know but I've used their personal internet banking system for a good few years now and have never had this issue.
But...... as far as their personal "24 Hour Internet Banking" service goes, I was told by AIB themselves that they only guarantee to have the system on-line for 20 hours per day!!!
I was working nights a number of years ago and had constant logon issues in the wee small hours.
Upon contacting AIB to complain, that was the explanation I eventually got!!
24-Hour Banking that's only available for 20 hours.......