Lookups on Merriam-Webster spiked on April 15, 2011.
The U.S. Postal Service admitted that the new Statue of Liberty stamp mistakenly features a photograph of the half-size replica at the New York New York Casino and Resort in Las Vegas.
According to one report, a "stamp collector noticed the error when he spotted differences in the ersatz statue's eyes and hair." (Slate, April 15, 2011)
Ersatz refers to an "artificial and inferior substitute or imitation." It comes from the German word for "substitute."