[roger_smith]

too lazy to read the above posts so if this has already been answered, oops.

The bulbs would all stay on and the source (battery) would be fine for a few reasons.

1. the bulbs are connected in a parallel block, making the copper joint a resistor
   
2. because the copper acts as a resistor, it acts like a load
   
3. Voltage stays the same, even when a parallel circuit is the type in question, meaning that if your source is 6 V, 6 V is what's flowing through each joint, dividing itself among each bulb in the joint.
   

The copper added to bulb 7's location wouldn't act as a resistor unless it was resistor wire, in which case it would heat up.