No Time For Questions, Just Give Me the Answers
Any chance of communication may be limited by time. So there is no time to question a person at length about their situation or no chance to question them at all if the communication is one-way. But what if the questions had already been asked before they were arrested and all they had to do was fire out the answers?
Using whatever technology or means of communication that was possible to them a prisoner could quickly deliver a set of answers to a short list of predetermined questions. There would obviously have to be agreement on the set of questions between the concerned parties before possible arrest. Or perhaps an international set of Yes-No answer questions could be agreed on regarding the basic human rights of a person who has been arrested.
The advantage is that using this system would allow the prisoner to send out a more informative message in less time.