CAESAR really doesn't need to make an audible announcement each time a pipe size or wall thickness changes, does it?

Likewise, since we have undo in case it happens accidentally, do we really need a dialog box that tells us we're deleting a bend?

I'd suggest adding a setting to stop producing these, as they're likely programming artifacts left in from debugging the software, no?

Maybe. Double-clicking a check-box for an auxiliary field will delete the data (if it exists). While it may not happen often, every now and then someone double-clicks the wrong check-box. I think that warning dialog saves people from this mistake.