The fist thing is test it by uploading yourself and see what happens.
Bear in mind when using list uploads to programs:
If using the Marketo Program connection to an SFDC campaign, yes it will sync all to SFDC regardless if they are ready for a sales conversation.
Even if its a static list local to that program as all members will be given a default member status and sync automatically.
If your not using the program sync and your using the flow action ’Sync to SFDC’ in a smart campaign then they all won’t get syncd unless you build it in to the trigger or schedule your batch campaign.
If your uploading to Marketo Database area and into a static list, it will sync to SFDC if you have a global smart campaign to sync all leads on Marketo lead creation.
Hope some of this makes sense…
Edward has it right. We used to sync at the program level i.e. automatically but we no longer use that and instead use flow steps in a smart campaign to 'Add to SFDC campaign'.
The reason is similar to the one you describe - we were finding that lists such as direct mail were appearing with our agents in SFDC before the mailers had arrived.
We therefore moved to smart campaign triggers so that contacts only move to SFDC based on triggered success criteria (such as attended event, email/landing page engagement etc.).
Thanks guys, this is super helpful!