I´ve been in Brazil for the past two months and have not seen anything of the sort. In fact, in all large cities, gas is piped, not distributed in cylinders by Fur Elise blasting trucks. In the rural areas, cylinders are delivered to grocery stores (again, no blaring trucks) from where they are collected by the interested parties. So, I would say it is not true.
I have heard Fur Elise as a mobile phone ringing tone on occasion though (in several countries). althoug it surprises me no one has yet thought of using Sorbji´s OC for the purpose.
Best wishes,
Bernhard.