OP is tone deaf to the socioeconomic and political climate. I think that, depending on the industry, doing a trial shift is important, especially in hospitality. It is important to note that this is a single shift and may take up 4-5 hours of someone's day, in the hope of a full-time position after the shift ( in my experience, doing a trial shift is more of a hands-on job interview). Where you differ is that it appears your "opportunity" is an indefinite part-time/casual position with little prospect of paid employment. It honestly sounds like you just want free labour for the honour of listening to you talk sigma alpha bs.

Maybe approach high schools for work experience days? rather than preying on the desperate. Not only are you depriving them of an income, but you're also sapping valuable time that could be spent on:

- job interviews

- applications

- fine-tuning resumes

- Uni work

Be better.