When a new weapon or a weapon which has ran out of ammo and is no longer in the inventory (grenade; there may be more) is picked up the game equips the item, the feature is sometimes called as "auto weapon switch". Half-Life 2 doesn't detect cl_autowepswitch 0 command.
1 Answer
This appears to be a bug introduced by the 2010 Orange Box engine update. From the pinned bug report thread on the now-closed former Steam forums:
Bug Title: Auto weapon switch always on.
Bug Description: Cannot turn autoweapon switch off "cl_autowepswitch 0" is unknown command.
