Where is this "return it" frenzy coming from? The moment he returns the bass, he is out $70 (what he paid minus shipping minus his return shipping).
If seller would give $100 refund, he would end up purchasing a deluxe MIM for $380. Since it is very very rare for a pickup to go bad, it's likely a wiring problem. The body can be easily repaired as well since the lost paint was in the box (I would repair it myself, but I am good at this kind of stuff and I have proper tools).
So if he decide to sell the bass, he would be better of than returning it at any price higher than $310; which he would easily get for that bass.
Econ 101