"no free immigration, no free trade"?
In other words, should freedom of immigration go hand in hand with free trade?
IMO, yes. All 4 freedoms are needed for "balance" (capital, goods, services, humans)
In other words, members of a Free Trade Area or Zone or Agreement (be it an FTA or a Union or the WTO (or a new, Mach II (deeper) WTO within the WTO) should allow for freedom of immigration. "No free immigration, (then) No Free Trade".
The freedom of a human, an "Eathling" to live and work where-ever on this planet he/she wants (provided he/she does so legally, ie pay his/her taxes, abide to the laws of the state, etc) is IMO fundamental and over-looked by many otherwise humanists or pro-liberty or freedoms proponents. This right should be automatic and limited only in certain cases instead of the exact opposite which is the case nowadays!