system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are large public places like amusement parks and stadiums able to enforce bans? Are there not too many people to keep a list going that’s effectively monitored?
gpt
They are not designed to block all access, they are designed to give the park grounds for charging them with criminal trespassing if they cause trouble in the future. 

But some effort is put into blocking access such as posters of banned people being at the ticket booth or gate, and they use facial recognition programs with surveillance systems in some parks.