@Ernest Bywater
My understanding is in the USA anyone can be a preacher and anyone can start a church. However, if you want to collect tax free donations you have to apply to the government for approval, otherwise any money given to you is taxed as an income.
While there are no restrictions on which religions are or aren't valid, there are laws governing activities of churches. Basically, if you're a non-profit, you've got to document how you spend your money, and for churches, you were (until recently) required to limit what you say politically in association with your church (i.e. no telling your congregation to vote for candidate X, or that voting for candidate Y will condemn you to hell for all eternity). Sadly, since that restriction was overturned, churches are now becoming unregulated fund-raising groups for specific far left/right viewpoints.
Most times off-the-wall churches crash, is when they've committed specific crimes (polygamy, child sexual abuse, prostitution, and yes, outright murder on their 'church' grounds). Then, when the government (i.e. either Police or FBI intervene, they 'resist' and most end up dying by their own choice).