I think the TLDR is a little more than that. Importantly, it's really not just about notice, it's perhaps more about being able to quash a summons. That is, the

I think the TLDR is a little more than that. Importantly, it's really not just about notice, it's perhaps more about being able to quash a summons. That is, the rules state that you can only file a motion to quash a summons in response to a notice. With no notice, you have no standing to quash. The law was always clear that for a collection action, the IRS doesn't need to provide notice if the records they are targeting in a summons are for an account the delinquent taxpayer owns (or more specifically "has a legal interest in"). In this case, 3rd parties were arguing that the IRS had to give notice because Mr. Poselli didn't have a legal interest in the account records that were the target of the summons. Supreme Court basically said (unanimously) that's a BS reading of the law.