Surely the gedolim will ok demonstrations when they realize that the boys lives are in mortal danger every minute. Certainly, a local Rov would give such a psak which people can be soimeach (i.e. rely) on, considering the situation. To live under such barbaric, cruel, inhumane and psychologically debilitating conditions is a saconos nefoshos (i.e. a constant mortal threat to life). Japan is in clear violation of International Prisoner and Humane Laws. They are rotzchim, achzorim, true ovdei elilim and shocnei ofor. They boys have been shown to have been ‘set up’ by criminal elements. There are many groups and organizations who protest and have protested against the Japanese, that can help our cause.
The lives of the other 2 bochurim sentenced to 12 years imprisonment, and of the bochur newely sentenced to 5 years, are in grave danger. They could be in the state of a ‘shoitah’ i.e. a ‘basket’ case mentally or lose their mind, or their lives (chas v’cholila). It won’t make much difference in the long run (may be too late), but in the intemediate term, freeing them will give them back their lives.
Demonstrations from our point are painless, a chance to do a fabulous mitzvah, help our brothers and show achdus with klal yisroel. It also shows great ahavas yisroel, emunas chachomim, ahavas torah and yiras shomayim and is a great kiddush hashem. You can also get plenty of fresh air. Bring a sefer along by all means and you won’t have to lose any time from learning torah!
Because of the bad economic situation worldwide and more so in Japan, any boycott of Japan will yield quick results and they will free or transfer the boys.