You can get "arbetsbefriad" / "Exempted from work" / in the UK called Garden leave / Gardening leave and you leave early. But employer decides.

>I would expect that in tech they'd allow them to leave early because employees who have chosen to leave the company are some times not the most helpful to keep around for months

It's called work ethics. Have some pride. Also if you bail without garden leave, you have to pay.