blacklist usernames that may be related to vietnamese "kubet" spambots

[PF94]

for a few months now, it seems like there's been a wave of vietnamese gambling site advert bots flooding websites. all they do is edit their profile with links to potentially malicious gambling scam sites. this hasn't affected squarebracket yet, since the site's small as shit, but i still want to automatically prevent it.

the only idea i have on how to implement this is that

1. check if the ip is from vietnam (i don't know if they use vpns or not)
2. if so, filter usernames if they have "bet" or "88" or other stuff in them (88 is considered a lucky number in asia akin to 777, this is unrelated to nazi dogwhistles)
3. if the username has any one of those in their username, then ip ban completely.

[PF94]

requires geoip which has iffy licensing