Well, the show does not go on then 
We are controlling fixtures (lamps) via DALI network to which we connect via tcp which is opened by a so called dali server. In this case, we are reading the power consumption of the dali drivers and log the values. In case the error is not caught, the flow gets blocked and no more measurements are done which can be seen in the db log table that no measurements arrive. The problem is actually that sometimes the dali server crashes and we expected to catch that (to restart the dali server process) since the tcp node should throw an error. However, it only works reliably if the tcp node is monitored by a status node.
Here is a picture of the subflow monitoring the tcp nodes (I don't think sharing the code itself would help further):
