I can reproduce using Send To (it does ask for confirmation when using the Properties dialog): http://www.ventismedia.com/mantis/view.php?id=10685

It looks like the confirm modification to more than 50 files doesn't work for some modifications.

So I have it enabled (Tools -> options -> confirmations)

I select 51 files
- If I try to change the rating - the confirmation message box pops up.
- If I try to change the tempo - no message box - all files change to the new tempo. Same thing happens for mood and occasion.

Isn't a big issue unless I'm not paying attention. Than it is easy to update 1000 files with the wrong tempo.