IMHO this additional cost should NOT be passed on to other countries, America is financially in the toilet as it is so financially restricting trade is not the smartest thing to do, many many buyers on Etsy, Ebay and various other sites have stated they will simply STOP offering goods to the USA period as it will not be cost effective.
I also noticed as per usual Australia post have nothing on their site about it and currently only 'some' Post offices are charging the fee as many are still unaware, great way to run a postal company.
I dashed down the Post Office today in a panic as I had several christmas gifts to send to the USA, as luck would have it almost all of them went over the limit making it a VERY expensive excercise, (almost $80 more) as they were headed for different destinations. I pleaded with My Local PO Lady as there was nothing on the Aus post site and no signage reporting the increase so technically I could not be charged??? she said had been fielding abuse all day regarding the increase, she seemed tired and let me mail them at yesterdays rate.. whew...she did not seem happy at all.
PS> I was informed that this new Process via U.S Customs screening and checks, that ALL parcels will be delayed by 48 hours to allow this process for the foreseeable future....