A rather clumsy solution

I finally made up my mind and decided how to handle the issues I referred to in my previous post. Even though I hate this solution, I did add a comment in my help file and in my ReadMe suggesting avoiding using UndoLastChange and the rest. On the other hand, I provide (in my "Interbase" sample application an example of how UndoLastChange (and only this) can be used safely without concerning about braking referential integrity.
As for the matter of reconciliation errors, I followed a little bit more radical approach (even though still clumsy). I decided not to "publish" OnReconcileError in TKTClientDataSet, hook OnReconcileError to a custom handler that does some validation and "redirects" to another event a made called OnKTReconcileError. This way I added the functionality I wanted.
P.S. I hate this "KT" that I am using here and there when I am trying to point that something is specific on the components I've made. (This represents my inability of finding more descriptive names- probably lack of imagination!)