I think Dallas and John made the 500 subscriber rule because it's for content creators. They said they don't want a guy that created a count just to comment on others videos and posted one video in 2014 filling the spots - essentially they aren't a producing content. Some that want to attend just started a channel and are hoping to get the subs. I think they will if the start a build and hash-tag #NoNameNationals to their videos. Especially if they call out somebody and get a challenge going.