Segment Integration: Default List Name and Lifecycle Optimizer

Within the Segment integration's Destination Settings / Optional Settings, there includes a field for "Default List Name": 


Specifying a list name in that field adds a "list" parameter for *all* Segment "Identify" events (which is translated into a Sailthru User API call).
By definition, a Segment "Identify" event occurs when a user takes an action and traits are recorded about them. This includes their unique User ID (a Sailthru extid) and optional traits such as their email, name, etc. 

For example, if "Master List" is the specified list in Default List Name in the Segment destination settings, this forces the Sailthru User API call to use "lists":{"Master List":1} each time an "Identify" event occurs.
Because the "Identify" event can generally be encompassing, this can trigger every time a user logs in, registers a pageview, or takes another personal action on the client's website. 

This can lead to unintentional behavior with Lifecycle Optimizer (particularly if a flow was created with a List Join entry point that matches the same list specified as the "Default List Name" in Segment).

Therefore, it's highly recommend that the specified "Default List Name" from the Segment destination settings is removed if there is a LO flow listening for that same list.