There is plenty of fake or low quality saffron on the market. I’ve seen it online, I’ve seen it in grocery stores, I’ve seen it in bazaars in Turkey. I’ve seen people throughout my life acquire small quantities of saffron from Iran, usually through travelling relatives or friends, as years ago that was the only way to get it directly from Iran given the sanctions situation. They would rather get it from a traveler going to a source country like Iran, because grocery stores in the US had earned a reputation for either not stocking saffron, or stocking suspicious or low quality saffron; and always, always charging ridiculous prices.
But even getting saffron through a travelling friend to Iran presents its issues. Expats are not likely visiting Mashad / Khorasan (the area of Iran which is the source of saffron), and where the most current and fresh stock will be located; they are likely buying it from a bazaar in Tehran (the capital), and the saffron has been through a few middlemen – farmer > wholesaler > distributor > bazaar / small shop – and you won’t know how fresh it is, and the bazaar you are buying it from sells hundreds of other products also, so they are by no means experts on saffron quality. Then, the individual buying the saffron from the bazaar and bringing it to the US to distribute to friends and family – this person may or may not find and procure quality stock, and maybe they don’t know how to tell the difference. So my point is, not to say that you’ll never get good saffron this way, you certainly can. But it is certainly challenging unless you are going directly to Mashad / Khorasan.