Not that the public will know. But the max will be one of the most tested and scrutinised aircraft in years by the time it returns to service. Probably with a much tighter MEL and more specific procedures to make it a safe prospect. I.e a lot more scrutiny than perhaps even some other new build aircraft. Dont forget the 737 rudder hard-over accidents aswell. Hasn't stopped the billions of passengers since then.
I also doubt that many of TUIs customers will even know it's a Max until they turn up at the gate. And are they going to sacrifice their holiday and walk away at that point?
Then again they may not book with tui at all to avoid the max altogether......