^ that, to be sure. Prior to losing a recording. And as regular practice, it would be good if you could make a backup copy to a laptop, tablet or phone after the show and before moving the card to the player for travel listening.
Your question is dependant on the playback device. Most will play existing files on the card as long as they recognize the file format. Some may need the files in a particular directory. If the device needs to reformat the card to recognize it, it should ask permission first, upon which you can cancel the operation.
I usually play the files using the same recorder. That's pretty safe, such that I don't worry about backing up the file prior to listening while traveling home. Sometimes I need to use a different recorder as playback device- for instance, I record 4 channels using a Tascam DR2d, but the DR2d can only playback one of the two stereo pairs at a time. If I want to hear the full 4 channel recording I use a laptop to backup the files, and rename them on the card to conform to the file name / directory structure used by the Roland R-44, which I then use for 4-channel playback.