I see this get discussed all the time and have always meant to flag it.

I have spent a lot of time deep in ad tech and a ton of time specifically thinking about identity resolution for ads - i have never seen a DSP make a conscious effort to do "target every cookie that belongs to a specific IP address" as a default rule (or even an option) but I see DSPs automatically opting in to the Liveramp cross device map - is this what causes this behaviour? I am even skeptical that Liveramp can robustly provide this data at scale and fast enough, so I wonder if its almost alway coincidence?