The details are vague, maybe on part of it happening so long ago. From just the text it sounds like they didn't get explicit permission from the store manager, and it didn't exactly sound like they made it known that they were the ones doing it. It all depends on who and how he gave that 'can i shoot video' question and if they knew the extent. It's also not like floor staff are constantly watching those machines - if people could just hit escape to get out of the slideshow, they might have just thought they accidentally opened the camera/photos app and wouldn't have immediately alerted an employee to the weirdness.

I think it's clear that it was done with a sense of "it's legal so i'm going to do it" even if that wasn't verified nor approved by anyone.