Some thoughts on what I've learned concerning intentional groups, those who focus on spiritual/political/psychological change:

Follow the money, who is paying and where does the money actually go?
Pay attention to how language is used, is the language loaded with extra meaning for members only? How is language being used?
Ask questions, learn other opinions, do some research.
Is there a charismatic leader? If so, watch the person in action if possible. What do the group members believe about the leader?
When pressured to join anything, take a step back, give ourselves plenty of time to contemplate first. Notice if manipulation and seduction are being used.
We always can say No for any reason at any time. No one group or leader owns the entire market of possibilities.
College campuses can be a target of problematic groups. Youthful idealism and a desire to serve can be misused by some groups. Anyone in transition can also be a target.

I think of all this not as something to be unduly anxious about, more as information comparable to consumer awareness and education. Buyer beware, joiner beware.