we've been through this many times before, you can use the search function to look up the numerous debates.
for very popular shows - the ones that sell out in a minute or two - such protections are often put in place. some shows have gone as far as being will-call only, meaning that the person who bought the tickets must pick them up at the show then immediately walk in. zero chance of re-selling.
but this is overkill for 98% of the shows at the club, it's expensive, and it's inconvenient. why should the vast majority of folks have to pay extra, and jump through extra hoops, to stop a small minority? why treat everyone like a scalper when they aren't? ticket limits and will-call only rules only make sense sometimes... AKA rarely.