Hello Daniel, and sorry for the delay on this. We do monitor our community but are not able to get to all posts on a regular basis. With that being said, Trusted Sender emails will still be subjected to basic spam checks (such as SPF/RDNS) to confirm the trusted message is not being spoofed by a malicious party. This cannot be disabled, and prevents outside agents delivering spam and dangerous content to your users behind the label of Trusted Sender. Hope that helps.
Kyle Kerst
System/Network Administrator
SmarterTools Inc.
(877) 357-6278
www.smartertools.com