I would think the same would hold for arresting people inside a bar and saying that they were going to drive drunk later so we can now arrest them.
This is facist thinking and has no place in America. Many of the people arrested were staying at the hotels that housed the bar they were drinking in.
This is as bad as hate crimes, or maybe worse. Arresting people for what they MIGHT do. Should we arrest people standing outside banks because they might hold it up? How about gun owners? This is one the antis would love. We arrest all gun owners because since they have guns they might commit a crime.
If we allow sh** like this to happen with the bars it won't be long before they are doing it in other areas and maybe in areas you won't be happy about.
I should have mentioned I drink plent - and often in bars - so I'm no big fan of this.
Nonetheless there's a flaw in your argument: Its "public intoxication" their arresting the people for - not DUI.
All it takes to be guilty of that is to be intoxicxated and to be in public.
Lastly, I doubt you're correct re the "entrapment" argument. That's just one of those things you hear around bars. Entrapment in the legal sense means they somehow enticed you to do something you otherwise wouldn't have. Hard to see how that fits the cop outside the bar scenario.