ONAC churches have gotten busted on at least 3 occasions for cannabis so far - lost each case. So they are being watched and busted by authorities.
That being said - there has never been one single Ayahuasca related conviction in the USA. No one has ever been convicted of an Ayahuasca crime here and police are not really looking to get into that right now.... There isnt really any dangers or crimes associated with Ayahuasca use and there is no pressure from the public for them to stop Ayahuasca use.
The only Ayahuasca related court cases in USA so far were also decided in favor of protecting religious use of Ayahuasca. So there is an established precedent to protect religious freedom here. That being said, a few of the things that allowed the SD and UDV to win their cases were that they only had one sacrament, they did not sell the sacrament and kept it under lock and key, and they do not charge large prices that make it look like a business. They also are fundamentally concerned with spirituality and religion - not healing (which might make it medicine, in which case it isnt protected legally). ONAC would most likely lose any case they have because they use more then one sacrament and because they sell everything for large prices. Also - you are not legally allowed to serve the sacrament until you get a DEA exemption, so that would probably be another point against them.
I think if police are going to court over this, they want to really make sure they will win. They will probably spend a lot of time collecting as much evidence as possible, and they may even wait for someone to screw up and get hurt first. They dont want to waste money on a court case they will lose, so they will probably make sure they have a perfect case against someone before charging them.