Might as well jump: Van Halen suffer major malfunction onstage

In spite of those that said it would be a car crash - the current Van Halen reunion tour seems to be going pretty well... until now.

Gizmodo.com has kindly posted video for the whole world to see of the band's recent synth malfunction during their encore of mega-hit Jump at a show in Greensboro, North Carolina. Instead of playing back the prerecorded synth part at 44.1K, it was played at 48K, resulting in this

Two things:

1. Why didn't they just stop the song and start again?
2. Does the crowd actually notice?