fun fact: if you paid your collateral to get your loan, ESPECIALLY if you use altcoins, lenders earned at least 5% already, of course vice versa, loaners gets nothing at all overall. so, even though collateral protects lenders, lenders can use this kind of advantage to scam loaners.
Don't forget that lenders also risk a drop in the price of that altcoin. Check out Bittrex or Polo and you will see that 20-30% drop within a day isn't unusual even in the case of more or less established alts.