A pin without an object flow of a call behavior action in an I/O partition is assumed to model an object flow with a system actor.
This is why such pins should be used during "create functional interfaces" to generate flow ports on the functional block created based on the corresponding activity, but also on the system boundary, i.e. on the system object.
If the system object is re-used according to ticket #14 then it has to be considered whether the plugin should offer the possibility to manually map flows out of functional blocks to existing ports on the system block.
Closed in version 4.0