The availability of the State Machine flow charts from SDL in PlantUML is a sheer delight. It provides an alternative to the state machine style of UML which, most emphatically, do not make it easy to document asynchronous protocols. Whereas the SDL style it certainly does.
The style Gerhard is referring to is extremely useful to provide the reader of the diagram with insight into the various paths through the state machine.
One other advantage of the SDL style is that you can "factor out" parts which come together in the same (subset of) state(s) without the clutter of all transition lines or flow lines.
The automatic flow line completion of PlantUML currently implemented removes this advantage a bit.
My suggestion: Now it is possible to specify "stop" to end a flow which automatically finishes the flow from the previous "node" to an UML end state symbol.
Just add an "empty" stop !
(BTW the PlantUML stop for SDL is an "end state" from UML. If PlantUML is completely "compliant" with SDL, it should be a "X". However, the end state symbol from UML is fine with me)