applications run out of memory if not polling the pipeline bus
If an application uses a pipeline without handling the pipeline's bus, all messages that are posted by any element on the bus pile up in the internal queue of the bus. This will slowly, but steadyly, increase the process' memory consumption.
While it is certainly a bad idea to not watch the bus and there are several places that strongly recommended to poll the bus, I was still surprised by this behaviour. I rather expected to simply not being informed about bus messages.
At the moment, I don't see any possibility, to change this behavior and let the pipeline or the bus decide, if messages on the bus shall be dropped or queued. Once this has to be decided by the application, the application might as well just register the handler. Maybe someone has an idea, how this could be hidden from the application. If not, maybe the wording of the documentation should emphasize that you have to setup the bus to drop the messages that you are not interested in.