> not sure if we got to a quorum yesterday, but it looks like you just missed some background details, so assuming we might be on the same page now: 

we are not. I still would prefer start/stop (provided the appropriate interfaces are implemted), but then for example "react" when the service manager is requested. The start method contains other valuable information which is not problematic. 

> would you agree in throwing an exception if any provided service instance also implmenets startable/stoppable?

the above said, I will implement what you suggest