A KWS is not for working out if targets are wanted. I'm not sure what you mean by a basic data scanner, unless you mean a basic discovery scanner and that certainly won't tell you if someone is wanted. You ship's sensors will do that for you.
A KWS scans a ship for bounties outside of the current jurisdiction, for example, if you scan a ship in Federation space it could pick up additional bounties in Empire and Alliance space. The range on a KWS is low (I believe an E class module has a range of 2KM) and you have to hold the target in front of you for it to work, although if you keep the trigger down it will only slowly lose the signal until you reposition. Be careful when using a KWS, just because a ship has a bounty from another system, does not mean it is wanted in your current area.
