Often left unsaid in the "gift card" (or, "game key reseller" market) is that the items are acquired illegally and resold for a profit. This is money laundering territory, and is very easy to run afoul of the law.
E.g. https://news.cybersixgill.com/how-gift-cards-are-used-to-lau...
But yes! especially in b2b sells. I always try to be super anal about kyc with selling to business buyers in bulk, and avoid buying from them. I straight up stick to institutional suppliers to avoid this issue :(