alt Hacker NewsErm, no, that's not a sandbox, it's an annoyance that just makes you click "yes" before you thoughtlessly extend the boundaries.
A real sandbox doesn't even give the software inside an option to extend it. You build the sandbox knowing exactly what you need because you understand what you're doing, being a software developer and all.
I know 'exactly' that I will need internet for research as well as installing dependencies.
And I imagine it's going to be the same for most developers out there, thus the "ask for permission" model.
That model seems to work quite well for millions of developers.