Did you say service suddenly shut down will bring some trouble.
Not exactly. What I say is that client programs aren't used in the same way as server programs.
They are made for different purposes.
Client application is treated as something that belongs to the current user.
The user don't expect that he will be serving other users and he can quit application any time he wants.
So, client application serving another client applications is not a common practice.
On the contrary, server is meant to serve other applications.
Stopping server application implies much more serious consequences than stopping client application.
That said, separating client and server is usually a good idea.
