usually the speakers and monitors are run seperate from the snake, so noise is not added to your line signals. the signal line to the amps can run from the snake, but i am pretty sure not the powered ones to the speakers.
this is a good read on balanced lines;
Disclaimer: I make and sell Buffers. I also sometimes Modify, Build and sell preamps and amplifiers. My opinions are not intended to be sales pitches. I am a one man shop and prefer to spend time with my wife and family, i work full time on call and love to spend my spare time doing other things. I only make, modify or build things for those that seek them.