@Don L Not a single client of mine (think larger companies) accepts ZIP files as email attachments (and haven't for some number of years now) ...
I realise we are getting way off topic but I'm curious how you email 30 or more attachments as that is often the case for me.
We are encouraged to zip files before email to reduce multiple attachments, and reduce file size and to make saving attachments simple.
A zipped file gets scanned like everything else (password protected zip files are blocked) and at the end of the day it's internal email, the sender can be identified and is risking his/her job by sending anything malicious.
Whether it's zipped or not and end user makes the decision whether to trust it and open it.
I've never had a zip file rejected by any popular mail program Gmail, Yahoo etc. if it contains legitimate (harmless) contents except perhaps AOL if the user had opted for no attachments. I zip and send hundreds of files every month all over the world to business addresses also.