TBH I have no earthly idea how BS is collecting data, I know the guy who runs it supposedly works or did work 'at' a Walmart, how they're getting this seemingly unlimited access to pricing data at every store in these companies is beyond me unless they're tapping some internal api systems they somehow gained access to, or they are paying someone inside the company to funnel data
All of BS information is directly from retailers piggybacking off their internal websites (desktop site, mobile apps, in store scanners, etc). So the information on scanners work from a website that is only accessible for the most part in those stores. Some of BS information is just mass info from Target, Walmart ,lowes, etc websites that all customers have access to (I.E. Walmart.com). For example on Walmarts website you can check stock of local stores, BS just access that line of code that allows that to happen directly from Walmarts website and runs it multiple times for zip codes in the area to get stock numbers from a certain radius.
Think of it as BS is accessing lines of code and organizing multiple strans of information into one convenient place.
Even with that information, stores still have to manually drop prices (on some items, not all itmems need to be dropped by the pricing team) on items, update inventory count, remove items that are deleted, etc. BS isn't wrong, it's stores that aren't updating as they arrested suppose to.