[sidewndr46]

For Nazi Germany the "fake traffic" would not be needed for all the services. Key change happened at midnight Berlin time by all operators. The radio operators stayed up late into the night sending the personal correspondence of the various officers to their families. The codebreaking process used this huge volume of messages to feed into the "cribbing" process which aided in recovering the traffic. By the time they had extracted enough of the key to decrypt traffic, normal military communications had started

[mannykannot]

Thanks - I was unaware of that until now. It appears to be a major operational security lapse.