I play in rock and jazz bands.
I’d be thrilled if 40 persons (other than family members) showed up to one of my gigs.
That is because you have class.
What this woman did was disgraceful - she walked out on an audience. Since her act wasn’t advertised, very few were aware she would be performing. It really doesn’t matter the size of the audience, they deserve to be respected. Brandy let her ego get the better of herself.
As a performer that is what performers do: they perform. Whether the audience is huge or small, or even nonexistent doesn’t matter. She should have put her heart and soul into performing.