Now a far more effective way would be to send a large number of encrypted messages to force them to spend CPU time to decrypt everything, even the messages which just say "Hi Mom!"
I handled an international custody case years ago. At the time the agency coordinating this was the National Center for Missing and Exploited Children. When I tried to translate that name into Spanish, it always went and came back as “exploded” children. Opps. I used a bad word. Sorry Jim.