Is it true the VCA can be called to active duty ?

While technically true under federal law, this is never going to happen. The last times the VCA went into federal service, was during the War of 1812 when the unit was the first to volunteer in New York State, and during World War I, when the VCA raised and volunteered several hundred members into service. While a few of the members were sent overseas on behalf of the U.S. Army, most were pressed into State duty guarding the reservoirs and been available as the state required.