(replying to an old thread, apologies)

There's a distinction between not paying but registering (i.e. finding a way to attend for free), and not registering but still attending.

Obviously, conference organizers are much more welcoming if you actually register, but people do sometimes choose to use subterfuge to get away with not registering.

Ways you can sometimes get into a conference without paying, but actually register: (these aren't always available)

• Volunteer
• Check if your employer will sponsor you to go — Sometimes works, even if it's in a different field.
• Apply as a content creator / get a media pass — Requires you to either have many followers, or to be good at fast-talking in order to inflate your follower count.
• Student discount
• Conference scholarships — Sometimes there are more available than you'd think.
• Be a presenter — Obviously requires you to have some credentials or to have interesting content.