Article 37 says, "Each full-time seniority driver in the center must make an election to opt-in or opt-out . . . "
The Contract doesn't say what happens if a driver fails to opt-in or opt-out. If anything, a driver who fails to choose should be considered an "opt-in" since that is the default position, and preserves his options to make an under-9.5 request and, if necessary, file a 9.5 grievance in the future.