Are you saying that those freepers renounced their citizenship?
As far as that goes, I'm in the (two-year) process of moving permanently to Panama. Citizenship will depend on what kind of residency permit I can earn. If I can earn Panamanian citizenship, I shall, and give up US citizenship. The whole process takes about 6-7 years.
BTW, re taxes. If one expatriates but retains US citizenship, one is still required to file income taxes annually. In some cases, up to roughly $92,000 of income can be tax-exempt for US purposes, so it pays handsomely to set up one's affairs so that one does qualify for this exemption. Panama does not tax income earned outside Panama. One must also file a couple of forms annually with the US Treasury Dep't.