I was surfing the internet today and noticed that the state of Maryland has laws protecting investors who are suckered into MLM schemes.
They are apparently entitled by law to a full refund on unused merchandise for 90 days. Not sure if this applies to the membership fee or whatever other money they have to shell out to the MLM, but it's a good start!
I imagine some other states probably have laws like this too. Something to be aware of if you're trying to get out of an MLM scam.