Roll-over switch maybe? Prevents fuel getting to the engine if the car is/has been upside down? I can't say I've ever heard of a switch being referred to as this but I'm just thinking what it could be and what purpose it could serve.. You don't mean the fuel cut-off switch under the passenger seat do you? This can be accidently pressed and will prevent the car starting through lack of fuel.
I dont know if thats the same, roll switch and fuel cut off switch, my car is on a jack now ( one side ) and it wont start, just fires once and thats it. alfa cant be that sensitive and not starting up just because one wheel is off the ground???