Their resumes have all the right keywords, and refer to "projects" they've worked on, built with all the frameworks and tools currently in fashion. They've practiced their interview technique and can talk confidently about continuous integration or opine about React vs Angular or describe how well they cooperate with their teammates.
If they don't get the job, they'll politely ask for advice on how they can do better, and maybe ask for a coffee date, so they can learn about the industry and how to find a mentor.
If you don't look closely at the resume or ask explicitly in the interview, you might think they have actual work experience, but they don't, it's all just coursework.
So I'm a bit ambivalent. Yeah, we desperately need more developers in the tech world. Yeah, startup culture is ridiculously tribal and unfairly biased against those who don't know the secret handshakes. But 3 months does not a developer make. When I'm hiring, I now look very skeptically at candidates that have been to a bootcamp. Experience has taught me that interviewing them is usually a waste of time.