Kasparov has forecast the possibilities, I think.
He may feel the cause worth risking his life.
You wrote, "He may feel the cause worth risking his life."
No doubt, but one should only sacrifice to gain advantage. I see no advantage to his cause if Kasparov is imprisoned, assassinated, or somehow compromised. The journalist, Anna Politkovskaya, was murdered for the cause Kasparov believes in, but I think the world would've been a better place with her in it. Same for Kasparov.