This feels like something that is only remotely feasible for contractors or recent grads living with their parents. The interview process is enough of a logistical PITA for most of us. Extending it to a week is comically stupid. Besides, we already have one week trial periods in the USA. It's called at will employment. It would be nice to say take a month and try out 4 companies before making a move, but I can't see how that would ever work for your average senior dev with a job, kids, and a mortgage payment.