I must admit that if The Sharing had been a club when I was in high school I probably would have joined and probably would have been tricked into becoming a voluntary controller. I just had that sort of personality. I kind of went with whatever my friends were doing, and I didn't want to be the dissenting voice. Since we were all very active in the school I see us joining The Sharing and becoming full members together, not realizing our plight until too late.
Now, it would depend on the situation. As was mentioned above, it depends on the situation. If someone had a gun pointed at me or someone I loved I would take infestation. If I was guaranteed a YPM Yeerk I would probably accept infestation. If I were in the Sharing nowadays and got to the "full member" bit I don't think I would become a voluntary, but at that point its too late for you regardless - I'd just be involuntary.
So basically, no matter how you look at it, I'm screwed.