It should be auto released if one party didn't put up the funds after a period of time.
I don't understand why you have such a difficult time understanding unless your just trolling

Explain to me why a seller would have to put anything up besides a small fee?
Because you're both entering into a contract or agreement, you both have something to lose if you both don't fullfill your end of the bargain.
Here, I have to explain to you like you're a two year old?
Seller has to sell something and send it, and buyer has to pay for it.
Two things that have to be upheld. It is a mutual agreement.