Stuff like this is why physical pentesting is so effective. If you sneak into a company and stick a raspi in a corner, nobody tends to notice a black box amidst a bunch of cables. But that black box can attack the dev machines in a variety of ways: it can be a honeypot wifi AP until someone accidentally connects to it, at which point you have creds for the real network. Then you can connect to the real network and look for workstations to attack. Or, as this article points out, you might be able to use a tricky bluetooth attack to get onto the workstations directly.

I'm not sure there's any way to protect against this. Physical pentesters tend to get caught less than 10% of the time. It's very easy to sneak into a building if you know what you're doing and have confidence. And "knowing what you're doing" generally consists of "dress up like a construction worker xor interviewee."