I mean, the act of people scalping stuff has existed before the digital age. Even a century ago: scalpers would pay a third party to hold a spot in line on purchasing concert or theater tickets to resell at a higher price since the internet didn’t exist back then. Like, in the 90s: scalpers showed up in person (paying someone to hold the spot for you whilst in line) for acquisition of the product, that’s how they’ve done it.
At the time, pre-orders for an upcoming console or game were done in store (you physically went there placing an order after seeing an ad on TV or a magazine). But, how common were scalpers during that era? It would be like a group of scalpers pretending not to know each other or split into smaller groups heading to different retailers on buying the same product whilst playing as another customer.


Zero scalpers in my town.
Bought Half-Life on release day, by walking in to a store.
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If anyone would try to sell a boxed copy secondhand, there is no way to tell if the CD key had been widely disseminated, and therefore would be worthless.