Right, the term I used as "refund" was not correct. Sorry for that.
It's very interesting to hear different opinions, thanks for mention me @Andrea9 . In my personal opinion, the city, or the whole national I live- China, is a country generally lack of trust, and because of this, I want to share my heat of trust to people, so that they would learn a little bit about trust, even if I have to pay for my price. I had once have a glass table at the living room broken whlile guests' stay, and they told me that table was broken itself during their sleep, and my fist reaction was not happy, one would find it hard to believe a table would broken itself. And I have to be honest with you, that when I fist heard of it, I almost wanted to say I don't belive it would broke itself to the guest. But I let it sit, and then I said, well, as long as no one's get hurt, that's fortunate. That guest didn't say goodbye to me when she left the house(it's listed as whole apartment). And that was very unusual, as that is a super beautiful listing, and every single guest would say nice word to me when they leave. As time pass by, the guest started to talk to me via wechat message- a local social media similar to facebook- as I always added my guest on it just so as easier to communicate. And sometimes I wonder what was the truth. But it didn't matter anymore, because even if it was the guest that broke the table, that'd be always something in her, and she knows, and I think that is enough, and I'm willing to pay for my price for it.
At the very least, you can still claim to charge the guests if any damage, doesn't matter you have the security deposit or not.
Anyways, it's all about everyone's personal choice weather or not having the security deposite.