That's like accepting two sets of rules for the same game, depending where it is played. Tango originated in Buenos Aires and includes codes that have been respected and followed for 70 years. If I traveled to another city where I went to dance, I would wait to be invited by cabeceo. The rules of tango are the rules I follow. How are visiting dancers supposed to know the local codes if they are different from those in the tradition of tango? This would require an announcement by the organizer or posting the rules for all to read in several languages.