I seem to recall that policy in parochial grade school for a while.
In USMC Boot Camp (1966), we weren't allowed to talk amongst ourselves in the messhall until close to graduation, when things got loosened up a bit.
In Catholic school in the 1950’s we were not allowed to talk during lunch. Enforcer nuns glided silently throughout the cafeteria looking for miscreants. They were not to be messed with.