I think they mean the 1970s-style "pull-tabs" that disconnected from the can. These were frequently discarded as litter, instead of put in a proper bin. I can remember seeing a lot of them in road gutters as a kid.
I think that’s about pull tabs (the old kind where you removed a small disc from the top of a can) vs pop tabs (the kind where you punch a hole into it and nothing detaches).
Decades ago they used to pull completely off the can (think Jimmy Buffet "stepped on a pop-top").