Check in is not process governed and there is no e-mail notification possible for it. There is not even a chance to create your own extension.

Since check in is usually done into a personal repository workspace, only the user that does it should care anyway.  The deliver operation is the interesting one and you get rss feed notification for delivery. There is no e-mail notification on delivery and I would strongly suggest to use the feed mechanism. You could extend RTC to deliver a mail on delivery however, if you wanted to.

I wonder why you would want to get your mail box spammed with those kinds of mails. I certainly would not want to have my e-mail exploding with this kind of information.

 Hi Ralph,