Before I started loaning I googled around looking for issues people had because I was sketched out. I haven't found a single case of it. I found one reddit thread where a guy was complaining that he never received a payment, and all the replies to it were positive and a poloniex support member even popped in and offered to take a look for him.

Polo takes a 15% cut, and the people borrowing have funds on the site but tied up in other coins, so almost nobody defaults on a loan, and if someone did poloniex has always found a way to make it right. Of course the past doesn't predict the future, and a huge bear run could change things, but I feel safe setting out many small loans for <25% of my total crypto assets