Very good question and something I worried about too. I actually verified this in audacity against some lossless samples of the same albums I already had and th

Very good question and something I worried about too. I actually verified this in audacity against some lossless samples of the same albums I already had and the decompressed wav were bit identical for what I checked (interesting enough, they were at a slightly different offset, I had to use audacity, zoom in to the numerical sample values and shift the waveform until they matched identically). There's also the issue that if Tidal were selling FLAC copies (which cost twice the MP3 version) that are just FLAC encoded MP3s I imagine there'd be a lot of complaining and/or lawsuits.