Thank you for suggesting outbound content filtering. This particular issue has been proposed multiple times in the past. Rest assured that it is in our feature request list for future implementation. It is a significant undertaking to implementation this particular task, but we are well aware of the significant and positive impact it would have. Unfortunately, I do not have a definitive date as to when it will be implemented. I have added a link to this post in the backlog item though, and I will update this accordingly.