Until then, is there a way to block the /me command? Or is it possible to somehow detect it and have a bot take action when someone uses it?
In your custom chat client, you could block it, but there is no way (that I know of) to block it in the regular Twitch chat (web/app). You can, however, detect a /me and have your bot warn the user or whatever you deem appropriate. While regular chat messages are being sent as regular PRIVMSG command, messages sent via /me will be delivered as CTCP ACTION command.