At least today, it is not involuntary servitude or false imprisonment because nobody is being physically held against their will or physically forced to work. Yes, I know that there are tales that in the past people were physically held against their will. When was the most recent such alleged case? I suspect this is like the issue of coerced abortions, where as Tony Ortega has noted the last one no later than 2010.
[One thing I've found frustrating over the years is that I've heard about all of these cases about physical restraint, but nobody ever went to law enforcement with a charge of false imprisonment. What is law enforcement supposed to do without a complaining party? Seriously, people are going to bitch and cegos ain about the government not doing anything when the government received no complaints from anyone who was allegedly falsely imprisoned? Where everything is hearsay? And often anonymous hearsay? Seriously?]
Today at least, people can blow, people can walk out. Indeed, I've seen numerous people on ESMB say they blew.
Staying in because one wants to "stay in good graces" with the Church of Scientology is not involuntary servitude
Sadly, staying in because one doesn't want to blow, be declared, and be disconnected from all of one's family and friends is not involuntary servitude. As long as one is not physically prevented from walking out, it is not involuntary servitude.
I don't doubt that the Church of Scientology's status as a religion in the U.S., the First Amendment, and the analogy of the SO to various Catholic, etc., religious orders is helpful to the COS, but it: (a) is not necessary as long as there is no physical restraint; and (b) would not protect or insulate the COS if it did physically restrain somebody against their will.