All the RPG mods have some sort of system like it, either with EXP or gold or whatever. Medic script, atleast how it works on [Ec] TW2, has a trigger to on weapons change, if you go from flamethrower to no flame thrower (by dropping it) it heals the area around you and gives you a new Flamethrower. The reason it only really works with the Flamethrower is otherwise the weapon gets left on the ground; but flamer just disintegrates when you drop it. It's convenient because the only other way of doing it is through console commands/text chat, which arn't bad, but take time.