seems to be a thriving trade in siltech cables and so doubt others.
from the siltech website
"Second hand Siltech is a great way to save money without losing quality. But take care. Because of the high demand and very high prices for second hand Siltech some unreliable factories started producing lookalikes with full printing of our name and type. This is totally illegal. In general do not buy from non-dealers unless it is a sincere customer upgrading or changing his or her system. In 2004 70-90% of second hand Siltech products offered through Ebay and Audiogon were fake "