Honestly, those are the only shows I've been to over the past 10-ish years, and those are the only shows where I've seen this sort of nonsense, other than maybe one festival that I played at where the main act did it as well. Shitty local bands have been using backing tracks for at least 5 or 6 years now, to cover up the dact that they can't confidently play their songs live. The saddest part is that some of their prerecorded parts are full of mistakes, too. Who said anything about court or brought up legal issues?!