I've been a programmer for the last 30 years. I can solve any problem. I've created more than $1B value for companies I worked for in my career. That alone makes everything you said about cameras or strong vetting or online track records simply invalid.
Instead take the time to find out who you're talking to and if they make sense. If you can't, first hire someone who can. And if you're hiring so fast that you can't tell whether you hired the same person as who showed up, then you're hiring too fast. Stop trying to out-grow time.
I agree about the raising alarm bit, that stuff needs to happen very quickly.