Actually it is surprising how many people
in all innocence do not know the difference.
Colour xerox machines are so good these days. Also the reproductions of historical icons from Byzantine Museums in Greece pasted onto boards are very good. These icons come with a stamp on the back with the name of the museum. I have met people who in all innocence think the icons are not reproductions.
Also from Greece are hand "enhanced icons" including some with stamps. This means that certain features of the icons are enhanced with paint (not egg tempra) by hand.
By the way Rose, the last time this issue came up was on this thread a year ago:
https://www.byzcath.org/forums/ubbthreads.php/ubb/showflat/Number/233166/fpart/1This was when the writer had a sale of icons and you can see that people who were interested wrote to him via E-bay for clarification, especially for the "15th century" item which was a reproduction.