Aly & AJ unknowns to drunks in Aruba

Evidently drunks in Aruba have not heard of the best vocalists in the world. Listen on this video as the crowd goes, "They're really good." The crowd also had no concept of "Do You Believe in Magic" (Doesn't sound like The Spoonful). Image if the Dynamic Duo had hit them with "Like Whoa"!

The mystery is - why did Aly and AJ need to watch the monitor on "Do You Believe in Magic"? What's up with that?