I am 3.5 years out from divorce and ex has married the AP (who was my best friend).
She comes to all their events.
She insists on being on all email communication from the school, coaches, Girl Scouts, etc.
She attends parent teacher conferences (my children attend the k-12 private school I teach at. On my dime.)
She volunteers as a parent at the school. (again - my workplace).
She emails me and my new husband. I blocked her email. They created a new one.
She approaches us at these events and attempts to talk to us. (We ignore. Then I receive chastising emails from ex).
The list goes on and on.
So, to answer your question, yes.