To add to what was said above...
I've also played for choir's and PT's, coming in as the new musician, that have told me that I'm playing a song incorrectly, when they are singing off key. This is about the only thing that bothers me from time to time, when I know I am playing the song correctly. I may not play it like the previous musician (others may have a different style), but when I learn a song, I usually try to play as near as possible to the recording, because I may not have any idea what the previous musician was adding to the song if anything.
In these cases, I'll politely ask someone to play the song and I'll play along so as to not cause confusion with everyone, but it gets frustrating at times.