The "old world" custom of the sender's name/address on the reverse of a letter/packet is hardly known by the new generation in both Canada and the USA. I've had many, many mailings from Europe (mostly France) where the mail was returned to seller's post office... then rerouted back to the USA with the return address crossed with an X. It can be very confusing, sometimes.. esepecially when a packet's return address is just as large as the destination address and when it's highly decorated (forms/stickers).