The requestis: If you have an event that says: set badguy.value('damage") to 5 (badguy.value('damage')+5), and the player doesn't have a value named "cool", a new value should be given to the gunner and set to 0.
In this case if you have a family named badguy, and want this event to affect all of them you just have to give the sprite the family and it will work. Like it is now you have to add a new value each time you create a new enemy. Also, if you have events affecting the values of a family and then you give a new object this family which doesn't have that value, all conditions and actions affecting that value is removed. This is VERY annoying (know that out of experience).
Another example: If you have a family called "friendly" and an event saying that when you overlap friendly, the friendly's value "say" is displayed in a text object. With this event you have to give all friendly units a value "say" even if they don't say anything. With the system i request you could have an event that does something like (i don't have the energy to write like real code) If the friendly's value say is not empty; display the text. (you could right now use the "value exists" condition, but it would be easier this way).