Oh, no, it was using a massive amount of upload bandwidth. Before I discovered how to deactivate the stream, it managed to upload 56GB of data (according on my Google OnHub data usage page). In less than 4 days.
What I suspect is happening is that the new "video clip" functionality requires that all video from the device is uploaded to SmartThings cloud server. Then when an event happens it can generate the clip. That's nice functionality, but lordie...
I couldn't find a way to deactivate the upload stream in the Samsung app, but I can in the ST app.
Now I set it up so the upload is only happening in the hours that I really want it: evening between midnight and 5AM. And I may end up setting it up to run only during these hours when I'm away from home.
Yes, I can activate it manually if I need it, which is why I'm thinking of killing the SHM video clip except when I'm away from home. This functionality is going to cost $4.99 a month after the end of 2015, so I may just not subscribe to this service in the future.
The only issue then becomes it activates a bit slowly, and when you want to see what's happening now you're out of luck.