Out of curiosity, did they smell much exhaust?The girl in the back needs a longer stem (rimshot please) she's gonna mess up her shoulders/elbows/wrists.
I add 3 bottles of "Gonzo Grape" fuel scent (from JM Motors) to every 20 litres (5.3 U.S. gallons) of fuel.
Out of all the fuel scent varieties, the "grape fuel scent" is the most effective; masking any unpleasant exhaust smell.
The other fuel scent varieties were practically useless.
Ironically, i have had people try and follow me because the bike made a nice smell.
Considering she was being towed up steep hills (with an orange coloured elasticised tow rope attached to the bike in front) her shoulders/elbows/wrists shouldn't be giving too much complaint.