Rancher CLI confusion on StartOnCreate

I’ve been trying to create a new stack with Rancher CLI rather than Rancher-Compose.
I was using the following:
. /root/env.sh; rancher stack create MyNewStack -f /root/test1/docker-compose.yml -r /root/test1/rancher-compose.yml

However I was finding that it was starting the stack automatically, which isnt what I was expecting? If you wanted this then wouldnt you use rancher up ?

However, I did find that adding --start=false to the end of the command stopped it starting automatically, although I expected it to default to false, and only start up if --start was present?

Have I got the wrong end of the stick here, or is the default value incorrect?