Do you need to rinse liver?

I got into an argument about liver when I saw someone boil a tub of chicken livers by pouring the entire contents of the tub (blood) into a pot without rinsing the liver. I always though that the rinse was required for health reasons (and to also improve the flavor.) The other person insisted that she preferred the flavor of liver when it is prepared in this manner. I think she may be getting defensive about her cooking methods, but is this a safe practice? Is rinsing required or just preferred?