Last year when I did the MMWT just after Labor day, I ran into a woman between Trail Crest and the JMT junction. She had done the JMT in Tevas (sandals with heal strap). They were falling apart and her feet were freezing and beat up and she was in tears. I gave her my roll of duct tape so she could do a field repair on the tevas.

I'm sure it works out for some people and it is a super cool bohemian back to nature stunt....but.......