I wrote a service in C# to do it. Basically I created a FileSystemWatcher instance to watch the spool folder. When a new file appears in the spool, I read the headers into an array.
Then I check the headers. I check for two things:
1. The "From" line contains "System Administrator"
2. "Content-Type" is of type "multipart/report" and also contains a "report-type=delivery-status"
If a spool e-mail contains those two things, I move the file to a "Spam" folder outside the spooler so I can review it later. At first I reviewed them all, but now I mainly clean that folder up weekly without even bothering to look anymore.
It would be a ton easier if SM just triggered the configurable spool proc executable for these. It currently doesn't, so there's no other way to catch them.
You also cannot strip the receipt request from the original e-mail using the spool proc executable, because the delivery report is submitted before the spool proc gets it.
Also, I did not want to deny my users the opportunity to request receipts, and there's no reasonable way for me to try and be selective.
I want SM to stop sending them, but I don't want my users to not be able to request them.