When I had no and then little experiences in hiring, I twice paid upfront. BAD move! Both times the experience was either poor, time shorted, or awful. Recently, I was asked to paid after getting undressed and ready to begin the session...reluctantly, I paid. BAD move!
Never again for me. NEVER!
...I wonder, in retrospect, if the request after getting undressed may have been on purpose. Next time, I'll have no problem putting my clothes back on...maybe slowly on purpose to make the point...and leaving.