Native Islander Tribes! Suggestion

Just watching Dead Mans Chest and after seeing the native islanders It made me realise how good an addition the sort of thing could be in the game. Imagine on some islands groups of tribal people inhabit the islands, some are friendly and are another faction that give quests, however some groups will be hostile, fighting you when they see you on their island. However instead of killing you, you get captured and caged, then you’re crew has to come and save you, before a timer runs out. I think it could add some more life and risk to the game world!!!! What do you all think?