I worked in a PC shop in 1990 and we got RAM chips in bulk and in plastic tubes. The dealers would put in counterfet chips that would not work because of shortages. Then issue a refund later on. Some PC shops also ripped off other PC shops doing horse trading involving RAM or CPU chips. Had a high defective rate back then. Nobody thpught to examine the chips, either threw them away, horsetraded them, or sent them back to dealer for a refund.