If you are making a definite and material saving, then switch banks.
For example, if you have a mortgage of €200k on less than 60% LTV, it would seem worthwhile to switch to Avant.
1) A High Court case might be taken and lost - so you will be glad you switched
2) A High Court case might be taken and settled or won - but not rolled out to everyone else - so you will be glad you switched
3) A High Court case might be taken and won and rolled out to everyone. In the past, those who lost trackers who had switched were taken back by the original bank on the tracker - again you will not have lost out by switching
So for switching to be the wrong decision, the following would all have to happen
1) A High Court case is taken, not settled privately, and won
2) The decision would have to be rolled out to all customers
3) AIB would have the Central Bank's approval not to roll it out to those who had switched.
Brendan