Its kind of stupid that radars are used to lock targets for a heatseeker missile coming from SAM. Take the SA-8 for example, no need to lock a target and announce your presence to their RWR.
It could be that radar needs info on target range, bearing, speed, aspect angle etc.. but for most IR SAMs in this game, a simple track and shoot with optical sensors is much more deviant and closer to real life (not a real life serviceman, whistling dixie). If you saw the Saudi F-15 shot at by a SAM, the pilot did not release flares as he did not know he was painted by a radar, and we know what was tracking him, a FLIR scoop.