Maybe but I don't do critical listening on club systems unless I'm checking my own mixdowns. Unless the DJ is redlining (which they shouldn't be if they're competent) the audio should come out of the mixer relatively unmolested. My critical listening rig is a broadcast amp with two passive studio monitors.
Should also note I can't hear the different between well-encoded 320kbit and FLAC. But lower bitrates (256kbit and lower) on mp3 are audible.