PS3 Warranty: The Proof is in the Pudding

Or actually, the warranty statement:
THIS WARRANTY SHALL ALSO BE VOIDABLE BY SCEA IF (1) SCEA REASONABLY BELIEVES THAT THE PS3TM SYSTEM HAS BEEN USED IN A MANNER THAT WOULD VIOLATE THE TERMS AND CONDITIONS OF A SEPARATE END USER LICENSE AGREEMENT FOR SYSTEM SOFTWARE; OR (2) THE PRODUCT IS USED WITH PRODUCTS NOT SOLD OR LICENSED BY SCEA (INCLUDING, BUT NOT LIMITED TO, NON-LICENSED GAME ENHANCEMENT DEVICES, CONTROLLERS, ADAPTORS AND POWER SUPPLY DEVICES).

So it's true. Sony really can/does void your PS3 warranty for using non-Sony brand composite cables.