How about Business critical communications
The problem with deleting all messages considered to be spam is that a false positive might be a critical piece of time sensitive information to complete a sales quote, a registration renewal notice, a customer request, or something else that really needs to go through.
If you are going to delete all messages flagged as spam, ensure that the business users understands the ramifications, and that they can request white-listing for business partners and critical vendors, and that customers can submit requests through a web-based form or through a telephone call.
Any message that is quarantined somewhere where users cannot immediately access it can lead to delays.
Even if an admin reviews the quarantine folder twice a day, those messages are sitting for hours. Deleting messages can be looked at as a reduction in delay for any messages that are expected, as they either get to the inbox or they don’t.
For messages that weren’t expected though, the delay may be days long until the sender calls asking why they haven’t received a response.
Whichever path you choose, as an email administrator, there are several things you will want to have documented and communicated to your users, including a written policy to cover what the system does with spam messages, what the email team’s responsibilities are regarding false positives, and how users can get assistance with either checking the ‘spam trap’ or white-listing critical business communications. Having these policies in place and communicating them to the user base will help ensure everyone is informed, aware, and understands what is happening with email.