I would only worry about can-opening if you had like two legs supporting the slider.
Besides, it will likely flex and hit the body seam before anything starts slicing & dicing.
gussets 'can open' a slider tube? I'm not getting that. There is an added stress concentration at the tip attachment to the gusset/tube, but it lower than what the welds would see without the gussets.
You all are taking this too literally as if it applies only to sliders or sliders pictured in the thread, etc.
It's theory and practice that I'm discussing, not necessarily one persons sliders or even sliders in particular. Most sliders don't need a gusset of any type.
It's about how to gusset tube. The best way is to use another short piece of tube: