Unless it's Guantanamo. That's not in anyone's jurisdiction in any sense of the word. Clandiness or clandinicity is surely a matter of perspective. I could see that masonry may appeal to prisoners in the same way that religion would. Structure, hope, friendship. It might be a gang but so might a Bible study by that logic. There is more to be teased out here by examine the concepts of what is irregular and what is simply illicit. I do know masons that have been to prison, been duly masonically punished, but remained active Freemasons after. We have our own principles of redemption, mercy and forgiveness to apply. The one I am thinking of in one of my lodges was for tax evasion, was suspended masonically for 5 years, but welcomed back, not necessarily by everyone but it was before my time. You can get into some tricky technical and/or strict liability offences, particarly around things like sales tax for a business, as I think was the case here. Being held accountable by the law does not in all cases mean there was moral culpability. In some ways I hope there are groups of people following Masonic principles in prison. If you think of it as s fresh start, which is after all one of the points of punishment, then I don't see why say someone who was a criminal in their youth, could not become a mason (genuinely, morally, and with all sincerity) later on in life. We gave up the ideas that criminality is hereditary or brands you for life some time ago. Most of us have broken the criminal law by speeding; is the only thing that makes us better that we didn't get caught? Or that so many people do it, there wouldn't be any masons left if all the speeders got thrown out? When we do speed in a car, say in a suburban street, it's only moral luck that means one person kills someone in an accident and another doesn't. The culpability is the same.