I'm not a judge nor an Internet police officer but I'd say 100% illegal.
Also, careful with this Terry. There are days that I could get out of my car with my torque wrench in my hand and scare the hell out of those in the opposite direction, who, couldn't care less about their indicator before shooting left and unannounced. I'm a very cool guy, normally, but very few things in life gets my blood cooking for some reason, and this is one of those reason. I wouldn't be surprised that other drivers in your area have the same blood
especially if they are driving with an occupied baby seat.
Just make sure that your indicators are meeting DOT, or meet whatever safety standard in the area that you drive and you'll still look cool with only a Boxster I'm sure