Hiya, [OSX]
alias rew="/Applications/Renoise_Reg.app/Contents/MacOS/Renoise -ForceRunningAsSlave logicbus_renoisetemplate.xrns"
So I have Ableton Live running, and type rew in Terminal - Renoise starts in ReWire-mode (but doesn’t load the xrns, but that’s beside the point).
Now when I exit Renoise - it will actually kill System audio AND crash Ableton Live.
Every single time 
Starting Renoise without the -ForceRunningAsSlave won’t give me any of this behaviour.