If these people are buying the goods internationally they usually have to pay for them before they are shipped. For most businesses that means taking out a short term loan to cover the purchase. It’s a standard practice even in established businesses.

Lenders require insurance against the destruction of the goods. Insurance companies like to carve out exemptions in what they cover to minimize their losses. Acts of war are almost universally exempted unless the customer pays a much higher premium.

I expect to see online retailers in Russia ban the sale of military goods on the next few weeks. Insurance companies and lenders are going to increase the insurance premiums and refuse loans to operations that sell them.