No -- any prospect that is already a participant of a DemandCenter Campaign will remain in that campaign indefinitely. Even if their original associated list is completely deleted from the DemandCenter account, the prospects will remain in the campaign to proceed through the flow(s) as designed; they will not restart flows, repeat actions, or in any way deviate from the designed behavior of the campaign.
To learn more about the Campaign Start Action, click here.
To learn how to build a Campaign, click here.
To learn more about Campaign Flows, click here.