: DYou will have to be stupid to operate SAMs on automatic mode in peacetime.
Even in wartime there is hardly any reason to ever operating in such a mode. Not unless you are in so much trouble that you know turning on your radar is pretty much a suicide mission, so you set the system on automatic mode and high tail out of there before enemy SEAD/DEAD assets obliterate the SAM site, and just hope it managed to fire off some missiles and shoot something down before it was toasted.
The USA military operated the patriots in fully automated mode up to / during the iraq invasion and for several years afterwards.
They started to consider to switch off the automated mode around 2004, when they shoot down too many USA/British aircrafts : D
Since then the Patriots can switch the launchers to automated mode only with an approval from the central command.
However this means if an early warning radar detect an incoming missile it is only a move of a switch to engage it .