The standard practice at the many airlines I've worked at has been to set 9900 during the preflight. I have never seen 00000 in my life. I would never allow it. It's just instinctively wrong. The 900 signals something is wrong and needs attention. Every time I look at the FCU and I see it, I think QUICK, DO SOMETHING. Though, thankfully I've never had to rely on it. One of my company's had the R.I.S.E brief which was mandatory to conduct before the BEFORE TAKE OFF checklist.
Runway,
Instrument Departure,
Stop altitude,
Emergency turn. There are literally a hundred different ways to prevent this stupid mistake from happening. The pre-departure MCP configuration is where you translate your discussed and agreed plan into reality. If it does not reflect your plan then I would say you have zero situational awareness and probably should not be flying a passenger jet. Boeing even help you with assuring it does (Airbus does not btw)...
