I looked up this "Vow of Poverty" and wow yes, the org definitely covering their bases. Its insane you have to abstain from secular work to supplement your income and have to turn over any proceeds from personal work? So effectively you are completely dependent on the org for food & shelter while they can boot you out at anytime they see fit with no chance of remuneration.
All this in the guise of "voluntary work" while in fact its an "exchange of services" which clearly is employment. I just hope those who are being sent home have at least learnt employable skills and get a good reference from WT.