I've never been a fan of the "lets file a suit" action, though the OPs situation does come pretty close.

Myself, I would probably first try going through non-lawyer channels to get this issue raised to Marriott Corporate and the hotel GM. I would think that they would be very interested and be very willing to make sure something like that doesn't happen anymore. And the issue could be dealt with that way.

But I do agree with most everyone that this type of behavior needs to be brought to Marriott's attention and dealt with.