Had this exact thing happen!I did an open mic not long ago and got up with a guitar player I didn't know who asks us (myself, bass + guitar) if we know Proud Mary by CCR. Sure thing. So he starts the song off alone and I'm thinking, 'is he doing the Tina Turner version?', because the tempo is much faster than CCR's. So I play the song and once its over he says into the mic: 'Drummers, you can't slow them down." You ass...you started the song that way!!! I said to him "I latched onto and was watching the tempo from your leg!" Guitar players!