Have been doing some more work on this and have discovered a couple things. The first is that there is more configurability to RTCD than I remembered. And although I love the "Step 1 .. Step 6" instructions given, I think I'd rather see a more typical "Configuration Settings" page for the various options for RTCD, with maybe the instructions list down below. Things are kind of hidden the way they currently have the RTCD configuration page set up.
First, on "Step 3" under the "Config Changes" page. There is an "Advanced Setting" for simultaneous Real-Time Notification download operations". You can set this to "One at a time (recommended" which is the default, or "More than one at a time" which doesn't do what I'd like it to do. As I stated before, I'd like to see all things like downloads under the "Transfer Status" page and have it abide by those rules for the most part. ie: if I set it to 30 downloads max at a time, that limit should carry over to here. It should all be the same queue. However, what this does is allow an unlimited number of RTCD-triggered downloads to happen at once. So, if like me you have a script running to bring some nodes into compliance and it is doing 30 at a time and doing them quickly, you could easily have multiples of that # downloading through RTCD at a time. I think CPU becomes the limiting factor at this point! Not a good thing. This needs reworking guys!! As a bonus though, it is downloading the configs much faster! :-)
So, on "Step 4", under the "Config Downloads and Settings Page" there is a setting for emails generated due to real-time config changes. I had this set to whatever the default was, which I believe was "disable email notification" and "use html formatting for email" unchecked, while "Include real-time notification details" was checked. There were default values in everything but the "To" line in the email boxes. Now, the interesting thing is, I went looking for this stuff because apparently we were trying to send thousands of emails to 4 email addresses per week. The email addresses were "IT@acme.com", "Employee1@acme.com", "Employee2@acme.com" and "Employee3@acme.com". Now, it should be said, our domain is not "acme.com", nor are we affiliated with them if they exist. The subject was "Subject: SolarWindsNetworkConfigurationManager-DifferenceDetected ", which is similar to the default subject on this page ("NCM - Different Detected"). I cannot find an alert elsewhere that has these parameters. I've opened a case with Solarwinds, but I think if you don't have a "To" email address configured, and you don't have "Disable email notification" checked (not the default), that it sends the emails to these addresses. Have opened a case with Solarwinds to check and see if that's what really is happening.
So, you might want to check your outbound queues! Not sure if this was an NCM 7.3 thing, or something that started after our recent upgrade to 7.3.3...