Exactly. It'll have to be like a software license key: in theory you can share your key, but the service can just authorize and lock in the first device/entity that presented the license key. This kind of DRM is often annoying for regular customers since you may have to manually contact customer support in order to request a transfer of the license to another device you own, but it does help mitigate non-paid use to an extent.
This could be enforced for real-life events by handing out a wristband with a GUID QR code to the first person to demonstrate they possess the private key that owns a particular ticket token, then never handing anything out for that token again, and also triggering an alert if the same QR code is ever seen on more than one person (to mitigate "pirates" who might offer identical or similar-looking wristband material and "replay attack" with an existing assigned QR code).
There are probably other attacks I'm missing (including obvious existing stuff like people just sneaking in and evading wristband checks), and there are lots of questions about whether an NFT or decentralized blockchain is a smart idea for a given live event, but from a security perspective I think it should probably be feasible if an event organizer does decide they want to do it for whatever reason.
However, there are other analogues that I think are much less feasible or perhaps totally infeasible. There are some NFT... apps? platforms? companies? DAOs? that are providing some service where an NFT grants you access to something like a restricted Discord server. Even aside from how valuable or sensible that may or may not be, there's absolutely nothing stopping a token-holder from just sharing their Discord account email and password with as many people as they want. The platform and the Discord servers would have no idea if anyone's doing this and how many people could be sharing any given account. (Discord employees could potentially detect some cases but I doubt they'd play any part in this.)
For a real-life physical event, someone can't just copy your body and make it a shared proxy for pirating, but any NFT ticket use case short of in-person events is probably often just going to rely solely on the goodwill of people to not abuse/pirate things, and we all know how that goes - especially in anonymous online communities.
The rubber-meets-the-road real-world crossover part is where NFTs and "Web 3.0" in general tends to become really shaky. I'm still mildly optimistic about it in the long-term, but I think a large percentage of existing use cases are going to fizzle as pointless dead ends that are surviving purely based on flavor-of-the-year hype and fad waves. Things are obviously stuck in one such fad right now.