I'm just going by what their policy says. It says that every single item included in the original box must be returned, or there will be a deduction. I take this to mean all cables, drivers, add-ons, stickers, manuals, etc. The return itself is extremely easy, major thanks to newegg.com for that. However, I don't know exactly how they will handle the return of a Mobo (well I sent one back but it had everything so no problem. Well technically it had a different set of cables than it came with, but I sent it back with 2 80 pin IDE and a floppy).
Here's the portion of the RMA email:
Please note, you will be deducted for any missing part(i.e. Cables,Menu,Driver
disc etc.). The entire item must be returned. Whatever we send you must be
returned to NEWEGG.COM