Bter has been paying that 10% interest for at least a year.
The business plan for that is that they sell your coins now, and when you want them back, they buy them for cheap, (because most alt coins have gone to near zero) and give them back to you.
Have you noticed that there are bots trading on Bter? Who do you think owns them?
Definitely something fishy going on.
Has polo ever done anything wrong? Should I be trusting them?
Polo had a hack as well...... Google it...... they also have a bot. Place a buy order 1 sat above the top buy order, and see an order come up immediately above yours.
You can send my 500XCR to my address, which is listed in the Delegate 101 Club, (on the new wallet)