To link this back in to the original comment, I bought what was clearly a counterfeited Spyderco directly from amazon. They didn't seem to care, but did refund me. (The knife sharpened extremely easily - VG10 is a tough stringy steel that takes more than normal effort to hone)
I won't buy new knives from anyone but the manufacturer anymore.
Edit for clarity: Most fakes were unstamped or generic Solingen/Sheffield stamps. Most branded razors pre1900 are authentic. Only a percent or two of those produced were fake. Still makes authentication difficult. And to make it even weirder, some fakes were actually better made than the brand they were being sold as!