Quote: Lazzard @ 15th March 2016, 9:28 AM GMT
In short, cost.
To perform the song you just need to buy the publishing rights.
To buy the actual song you need the rights to the record/performance etc.
Sometimes they play bad specially recorded cover versions of songs in shops.
They're so bad I assumed they weren't allowed to make an exact copy of the song, and had to make it a rubbish only-vaguely-similar version.