I find that "frequently returned item" warning really useful. It's a reminder to look at the 2 star and 3 star reviews. Sometimes it's just a sizing issue. At other times some subset of people have a specific issue. The issue may or may not be something that affects me (e.g. some people can't operate something that doesn't have really clear instructions).
I do too, but I think it's important to consider that these are actually pretty different. In the Google example, the banner is being displayed because of something that isn't necessarily the fault of the dev and isn't itself an indicator of problematic behavior (and indeed is the starting position for all developers of a new app), whereas at least Amazon (presumably) is basing it off of actual performance data that indicate poor performance/behavior.
I find the “frequently returned item” warning totally confusing. It usually isn’t reflected in their reviews that I can tell….
I have to wonder if there’s some sort of strange meta where people search for one thing buy something and not realize that they’re actually looking for something else that’s difficult to search.
Or buy something and the warehouse ships them another. I bought something from amazon where reviews said about half the people got the wrong product, and I got the wrong product, returned it and got the wrong one again, and then they wouldn't let me try again.
In a twist, I had previously attempted to order the right product from a different vendor, but I put the wrong one in the cart, and had to pay a restocking fee to return it. They sent me the right one when I ordered it properly.