Presumably if the Swedish tax authority called you, they'd speak to you in Swedish, and you'd be suspicious if they couldn't. So if you wanted to run this scam

Presumably if the Swedish tax authority called you, they'd speak to you in Swedish, and you'd be suspicious if they couldn't. So if you wanted to run this scam on Swedish targets, you'd need to find a bunch of Swedish speakers willing to work for low wages doing something unethical and illegal. AFAIK, the only country with significant number of Swedish speakers is Sweden, a fairly wealthy country, and also the country where you'd be running the scam, vastly increasing the legal risk. On the other hand, there are countries which are poor, not the US, and have lots of English speakers, and these scams tend to be run from those countries, at least according to the callers' accents.