Because I don't know the ins and outs of this matter, I can only imagine it. I think the reason why others use your ID card to purchase foreign exchange is because at present, the state adopts a total control of $50,000 per person per year for foreign exchange purchase and settlement. Generally speaking, each ID card can purchase 50,000 US dollars of foreign exchange and settle 50,000 US dollars of foreign exchange. If someone buys foreign exchange with your ID card, it means that that person bought it once with his ID card and can't buy it again. The impact on you is that you can't buy foreign exchange yourself this year.

Of course, I just explain from the perspective of national policy that there are always hidden dangers in lending your ID card to others, because others may not only use your ID card to buy foreign exchange, but also take this opportunity to use your ID card for other purposes. Unless you trust the person who lent you your ID card.