Is the volume auto-mounted on access on the client (outside of MC) ?
If so, a simple "check if file exists" would mount it.
A couple of points. One, I am trying to avoid the 4-second delay it takes to mount the remote volume when the client MC restarts. (For various reasons, the client doesn't run all the time.) Also, a constantly mounted remote disk complicates admin of the server machine due to "a client is connected to this machine, do you really want to do this" type of alerts. So I really don't want that remote disk mounted by the client all the time.
Why not just keep it mounted and enable the local playback option?
Because MacOS has terrible network file system performance. Even though I have a steady, reliable 300 Mb/s net connection on both client and server, it takes 5 seconds or more to fully preload a large FLAC file on the client so that it's all in memory. If I don't enable memory playback then the client will inevitably stutter. This is just a fact of life with MacOS's crappy network-mounted file system. Experimentation shows me that MC does WAY better at streaming its data than MacOS's net-mounted file system.
From another angle, is it fair to ask "why is MC causing this remote file system to mount when it has no business doing so?" It really should not do this, I can't imagine any good reason it does.