Wait, really? When I took a trip to Australia, I wound up getting a Japanese car from the car rental and was constantly turning on the windshield wipers when trying to signal.
Driving on the left? No big deal. Remembering where the turn signals were? Took the entire trip.
Of course, when I got back to the US and into my own (Japanese) car, the first thing I did after starting it was turn on the windshield wipers to indicate I was turning left out of my parking spot.