I am an IT guy, I was once had an employee trying to drum up some business by sending out batches of 10,000 emails to an email list they bought online, our organisations domain got blacklisted globally by SORBS and it took me 3 days to get us off their blacklist. During this 3 days we had no mail flow!
Some people think they are doing a good thing but they really should leave it to the professionals.
All just my humble opinion.