If that is true, it was not mentioned in the article. The relevant section:

On her speed dial, she has phone numbers for both the mall cops and the Metro cops. The musicians seldom last long.

What about Joshua Bell?

He was too loud, too, Souza says. Then she looks down at her rag, sniffs. She hates to say anything positive about these damned musicians, but: "He was pretty good, that guy. It was the first time I didn't call the police."