When swapping Eurocard boards, it is safest to first turn down the power supplies and then do the swapping.
Otherwise, it is sometimes the case that people plug in the board slowly and/or asymmetrically. This can cause the opamp to see one of the power supply rails without the other (e.g. +15 but not -15).
This can destroy some opamps. The true danger is that there may be damage to the board which you do not notice for several months, thereby leaving a timebomb for the next person.
Don't be an electronics terrorist!