29 C.F.R. § 785.28 Involuntary attendance.
Title 29 - Labor
Attendance is not voluntary, of course, if it is required by the employer. It is not voluntary in fact if the employee is given to understand or led to believe that his present working conditions or the continuance of his employment would be adversely affected by nonattendance.
Title 29: Labor
PART 785—HOURS WORKED
Subpart C—Application of Principles
Lectures, Meetings and Training Programs
§ 785.28 Involuntary attendance.