What would? Did you intend to quote me? I'm advocating looking at the details of someone's raider.io score to see if they just purchased a run or are running them regularly. You should be able to discern between regular users -- including those just running a single weekly -- and anything sketchy if you do that. And I'm not advocating punishing anyone, regardless.
My ultimate point was that if people are expecting to be able to spend a split second looking at a single number without doing any further review and have perfect success with PuGs they are going to be disappointed, but it doesn't make those tools useless. People just need to take the time to look at the details too.
Part of the tooltip tells you how many they've completed in time. Granted, it doesn't tell you per instance but you can figure it out by copying their URL and going to their actual RIO page if you want more information. When I'm making a group I look at 3 points quickly: RIO score (along with main if it displays), # of runs completed, and highest for this instance.
Yeah, I've never actually used the addon because I don't PuG; I mostly just keep an eye on my page on the website for my main just to scratch my completionist itch (still some 15s to go!). But from the website it's really easy to see regular players because you'll see they've worked their way up from lower keys, they'll have a variety of runs across different weeks and affixes, etc. It's a big contrast from someone who has maybe a few really low keys, and then one +10 for all of them in the same week, or one really high timed run with nothing else working up to it, maybe all their party members but them are from the same guild, etc. There are a lot of clues to look for, and while maybe nothing on its own is bad, they can add up to something worth avoiding if you see a lot of them and you're really try to weed out carries/purchases.
But looking at the details isn't just useful for that, maybe you want someone who has done a lot of your particular dungeon or that week's particular affix, etc. In general, it can just be a good idea to look at the breakdowns if one is trying to be very picky, whether it's to see how close their failed runs are or how often they run or if all their experience is limited to one instance.