Definitely babywear in taxi's - when we traveled through Malaysia and China, I wore DS in the Ergo in all taxis and private cars.
Also on some flights (mainly within China) we weren't able to get seatbelt extensions for DS who was traveling on our laps.
In those instances he was in the ergo on the plane as well, which was frustrating - just be prepared in case this happens. I was perplexed to say the least!