I have done so. I just don't go back. Nor do I take out a full page ad in the newspaper to proclaim my disappointment (a more appropriate analogy).

You seem to have tickets.

The OP asked what feedback they should give; something I would never do, as it's supposed to be the buyer's perception, not a groupthink thing. I replied with MY opinion. I'm pretty sure that's still allowed, especially when it is invited.