I can’t remember a cruise where I saw many people “hammered”. Folks partaking in drink and having a good time? Yes. “Hammered?” No, not often.
I guess it depends on your definition of hammered.
There are fines for leaving mid journey.
It is well documented am this and other travel blogs that these fees can, and often are, passed on to the passenger.
It would be interesting to see if this fine is covered in the carriage contract.
I agree there should be some receipt or paperwork, but in the end the fee is valid.
A dispute may facilitate getting documentation; I’ll agree on that count.
Other cruise lines are already charging for their version of the solarium. THAT Is the natural progression. Once one line is the test case that proves people will pay; others follow.