I have to agree with Paul Blank's notation:
If such a feature is implemented, please make certain to include the proper warning if the new feature is selected for use.
I would also consider making this selective-by-domain. I can see many situations where problem users would block and delete, simply because they were aggravated with a specific sender, and then open a ticket, or call screaming, demanding we "undelete" their messages.
Phonr: (773) 491-9019
Phone: (224) 444-0169
E-Mail and DNS Security Specialist
Network Security Specialist
Customer Service Portal: https://portal.chicagonettech.com
Security Blog: http://networkbastion.blogspot.com/
Web and E-Mail Hosting, E-Mail Security and Consulting