Yeah I thought about this too. The
US embassy website seems to make it pretty clear though:
If you wish to work in the United States for a temporary period you will require a nonimmigrant work visa. It is not possible to work on a visitor or business visa, or under the Visa Waiver Program (VWP).
Unlike some countries, the United States government does not issue work visas for casual employment. In general, work visas are based on a specific offer of employment. In most cases, a petition must be filed and approved by the U.S. Citizenship and Immigration Services (USCIS) before applying for the visa at a U.S. Embassy or Consulate.
Edited to add: She doesn't appear to meet any of the criteria for
a petition-based visa either.