I saw laptops like those on hackathons and always sort of assumed they were their personal machines. Kind of surprising to read here that some of those were apparently (company-owned) work laptops.
Not necessarily startup. You can see some laptops with defcon stickers, it used to be very common for infosec auditors to have work laptops full of stickers not that long ago.
Although, it is bad practice for read team audits, and some large companies don't like this kind of shenanigans for internal audits, so that may explain why it is less frequent nowadays