All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah,and that Muhammad is His slave and Messenger.
This dealing is a hiring contract (ijaarah) by institutions for those teachers and students so that they collect donations for them in return for a fixed percentage from the total sum which they collect. In general, according to the preponderant opinion of the scholars, there is nothing wrong with that. Shaykh Ibn Taymiyyah said in Majmoo’ al-Fataawa, “If the compensation is taken from the work that is being achieved, then it is permissible that it be a known portion.”
Also, the site of Shaykh Ibn Jibreen reads, “It is permissible that that aid be fixed, such as with a monthly salary, regardless of whether the collaborator collects a lot of money or a little, and it is also permissible that he is given a portion from the donations that he collects, such as a sixth, or an eighth, or one-sixteenth, according to the time and effort that he exerts, so that this would be an incentive to make a great effort.”
The fact that part of the donations could be zakah money does not have an effect because the charities that are authorized to collect zakah are representatives of the ruler in that, and there is no harm that they give the workers collecting the zakah a share from the zakah; and we understand that such charity associations are accredited and authorized to do that [collect funds].
The majority of the scholars are of the view that there is no specific maximum commission for the zakah collectors, except for Imaam Ash-Shaafi’i, who held the opinion that the zakah should be given to all of the eight categories of people who are eligible for it [which are mentioned in a verse in the Quran].
As for the fact that some of those collaborators are given a salary from their employer during their vacation, then this does not prevent them from cooperating with those institutions during their spare time while taking a commission in return for this cooperation.
Also, if the institutions do not give a commission or a salary to those who receive the donations [the volunteers who accompany the collectors], then this does not affect the permissibility of such dealings, and this does not render what the collaborators earn forbidden.
What is important concerning the people who accompany the fund collectors is the agreement that is agreed upon in the contract between them and the institutions that send them and which they work for.
Allaah knows best.