In the mid-2000s I was doing some consulting in middle America and noticed a bunch of Indian IT workers staying at the same hotel I was staying at. Since, I was Indian-origin, we engaged in some small-chat. They were working for a now defunct telecom giant (but contracted by one of the big Indian consultancies) on various software projects. There were there on not, H1Bs, but another class of short-term business-meeting only visas. They told me every 3 months a whole new team would cycle onto the project with a fresh set of business visas and the rest would cycle back home, rinse-repeat. They weren't allowed to "work" per say, and some of their colleagues got rejected at the border by more savvy border agents. But for every 1 rejection, 20 of them would get through.