I'm wondering how you some of you deal with this sort of situation:
We want people to fill out a form at our booth at a tradeshow. I want to set this up as a campaign so that if you fill out a booth, your SFDC status changes to visited booth. I want this information right away so it can be sent over to our sales team.
When we get the list from the show later and tradeshow attendees are uploaded, I don't want those who visited my booth's SFDC campaign member status to change.
If you are syncing leads who fill out the booth form in real time to your SFDC campaign with that status, then everyone else gets synced later, you can simply use an 'add choice' to your Add to SFDC campaign flow step.
Choice 1: If Member of Campaign "xyz" do nothing, otherwise default action would be to load everyone else as normal. This way everyone already in the campaign won't be affected while the rest are pushed over.