This is a good issue to discuss. In my DB I state on the first day, you may post what you like but if I or another challenge your statement, the student should respond to correct, amend or qualify a posted message. I read of the student's work for evaluation. If a student corrects an error, I acknowledge it and do not remove points.
Therefore a student is encourage to review the DB forum often and before the due date to make changes.
I encourage students be critical thinkers and keep civility at all times.
