It could be a scam, in theory. But this is also roughly how you'd expect a legitimate company to behave. They have a system that uses some cheap heuristics to guess whether or not you're a scam--and they do that for free. To actually investigate gray areas, they need human intervention, and that comes at a cost.

This is how, e.g., the legal system works. If you're accused of a crime, you can cheaply plead out or expensively defend yourself. It's also how customer service works: they can deal with ~95% of the problems people encounter by reading off a script, and they have to escalate the last 5%, sometimes at a cost.