What is the ruling on taking half the money in exchange for reclaiming rights from usurpers, under the pretext that their lives are in danger?

It is permissible to offer a known sum of money to someone who recovers usurped rights, and this falls under the category of permissible ju'ala (stipulated reward) by agreement. It is also permissible for the person to take a percentage of what they recover. This is permissible according to the Hanbalis, by analogy with mudaraba (profit-sharing partnership), contrary to the majority of scholars who prohibited it due to the uncertainty of the wage. For this action to be permissible, it is stipulated that it should not be highly probable that harm will befall oneself or any of one's limbs, in accordance with the Quranic verses and Prophetic hadiths that prohibit causing harm to oneself.