This is another silly claim. Cassidy says that policy is a gambling term. He doesn’t define it and I haven’t been able to find a definition on the internet but it is clear from Cassidy’s claim that it means some kind of payout.
Cassidy’s fake source for the gambling term is pá lae sámh, which he translates as ‘easy payday’. This is a mistranslation. Payday would be lá pá (day of pay). Pá lae means ‘pay of day’, so it’s a day’s pay. There is also a massive problem with the word sámh. It does mean easy, but easy is a word with lots of meanings. Sámh is the easy of Sunday mornings, long summer afternoons, a good night’s rest. It is tranquility and peace and lack of disturbance, so this phrase, insofar as it means anything at all, conjures up visions of a wad of cash lying on a sunbed drinking a cocktail. It is not the easy of easy money, which would be expressed in other ways, for example as gan dua or gan stró (without effort). And Cassidy was completely wrong on the pronunciation as well. Sámh is pronounced sow (like the female pig) in the north and sawv in the south, not as see.
Besides, why even suggest an Irish origin? What’s wrong with the slang word policy deriving from the mainstream word policy, which is ultimately of Greek origin and goes back to at least the 14th century in English? After all, the gambling term policy seems to mean some kind of payout. And insurance policies pay out when exceptional circumstances demand it. That’s what they’re for.