We include this flow step in the smart campaign of every program where a lead could potentially engage with this program (e.g., fills out form, downloads PDF, registers for event). You wouldn't however add this to a smart campaign where the lead hasn't initiated the activity (e.g., send email). This is especially important for leads that are imported into Marketo - in our case, we always choose "None" as the Acquisition Program during the import process. No program should be given credit until that lead engages with that program. Note the two different names used for "Acquisition Program" (for that "attribute" and "choice") that must be used here.