Thanks for the excellent info. Since you do not need to add a trigger to the campaign, and filters are optional - do you still need to run or schedule the campaign, or will it run each time someone from an engagement stream is added to the program? Put more simply, does placing a program inside an engagement stream make the stream a "trigger" for all campaigns within that program? Thanks!
You surely do not need to schedule the smart campaign. and indeed the engagement program will "trigger" it.
And, as written above the recommendation is that you add the "member of engagement program" filter.
Greg, thanks for all your replies in this thread. I am surprised that this basic info doesn't seem to exist in the doc on this topic: Add a Program to an Engagement Program Stream - Marketo Docs - Product Docs