That depends on the design. The most common one I encounter is fixed at two points and can't be extended without some amount of tearing, so I just keep tearing. I've never been the sort to not put the cap back on the bottle when throwing it away so it's a redundant feature for me.

That said, in the time since this new norm came in, I've lived in two different countries, one of which had signs saying to separate the cap from the bottle at recycling recepticles, meaning you had to tear them off.