No. In a Bitcoin transaction the fees are implies by in minus out. There's no way of knowing without a proof the value of a particular output, so if you accidentally spend one far below it's actual value you can end up paying an insane fee. People have lost hundred of Bitcoin due to bugs like this, like off by one errors. A malicious or misbehaving API could misstate the value and cause you to unknowingly lose money in this way if you blindly trust them.
