Montpellier residents can sign up for a free transport pass on the M’Ticket app and the TAM website. Photo ID and proof of address are required.
If fares were such an insignificant source of income before when residents had to pay, why bother ticketing at all when the only fare payers left would be an extreme minority that also happen to be your guests?
So much money spent on ticketing systems, apps, registration and other overhead that nobody needs and could be spent on improving the service instead if it was simply free for everyone. I highly doubt doing that makes any sort of profit. I don't get it.
I agree with your reasoning. But Montpellier is a quite a tourist place especially during summer. Maybe it still make profit with them it is not a smal minority.