Allow attendees join before host would work with API?

Please kindly advice if this can work.

When Site Admin Meeting setting, "Allow attendees or panelists to join before host (EC, MC and TC)"  is enabled,

Even the host using API to schedule a meeting, and the attendees to join the meeting with API,  meeting

attendees can join the meeting before host would work?

Greetings! In general, it is best to explicitly specify what options you want when making API calls. For your request, I would recommend making sure to add in the join before host options to your API call. i.e.:

<joinTeleconfBeforeHost>true</joinTeleconfBeforeHost>

There is a great example XML document shown in the API documentation at:

Cisco DevNet: WebEx Conferencing - XML API - XML API Reference