Wow Clay your numbers are low, we only process 2% of e-mail, rest gets dropped, and even then I still get people complaining about receiving SPAM.
So what I used to do was pull up the logs and let them know how many SPAM e-mails they got in the last 24hrs, and in order to help use reduce the rates, please allow me to send all of them to you. You mark them as Spam or not, and then let me know.
Never had anyone take me up on that offer.
DDOS attacks are a dime a dozen, and literally cost pennies to get some one to fire one up. Students try and use them all the time against us, try to knock out the testing systems. Give them credit for trying. Not sure why they would pay a few bucks to try and miss a test, when they could just send a crappy tweet, and run the risk of becoming an FBI visit recipient.
When I retire I might have to write a book of all the stupid shiz students do electronically. From bulling to translated bomb threats, I have seen and tracked down all of them.
But I will say some of the adults have really freaked me out, and I have had several occasions I did not want to do the research to see if the offense occurred on our equipment.