When Reference Recordings issued a 45 rpm recording of Respigi's "Church Windows" a critic actually made the mistake of listening to it at 33 1/3 rpm. The amazing thing is that the critic actually acknowledged the mistake in a subsequent report (the piece is not an often heard warhorse). It is easier to be fooled and not recognize such a mistake with non-vocal classical pieces than most other kinds of music.
During the 1980's I was demonstrating my system to some non-audiophile guests, playing among other things the last two movements of the Reference Recordings 45 rpm release of the Berlioz "Symphonie Fantastique."
Quite a few minutes into it I realized that I was playing it at 33 rpm, but I was too embarrassed to own up. After it concluded, the assembled multitude all appeared to be genuinely impressed.