Has this happened to anyone? What would happen if you showed up and find that your ticket is invalid. I'm guessing it varies by venue but is there any recourse? I can't imagine they'd just turn you away without at least a little investigation.
neither the ticketmaster folks nor the venue folks tend to be super compassionate in my experience. it's a real mess though, the venues often have no in-and-out privileges (possibly due to how scanning invalidates some 24-hour key), so even as a law-abiding consumer, you're stuck at an event for the whole time just to deal with ticketmaster's implementation details.
i'm sure others have said this, but that is definitely a business that wants disrupting. there's so many bits of tech that could make this experience better and safer for consumers, but i suspect ticket fees are more profitable than user experience.