Like I said, I agree with what's being stated 100%. With high quality cables (little larger than 16awg), I run 10x Neptune cubes each with single PCIe cables up to 280W, and they're hardly warmer than ambient.  

Do I know how they would find out I was running 2 instead of 3 PCIe cables on an S7? Maybe not.

Is it wise to advise others to go against something they have made explicitly clear against doing (for whatever reason)? No.

Will I do it myself? Of course not

The splitters that dogie linked to are the right way to go, for how much they cost they give you peace of mind in regards to warranty.

Edit: Here's a flashback