I write real time, video based FR. The company I work has a strict policy that our sales, nor any partners even respond to Chinese company queries. The thing is, regardless of what they say, you'll never get paid AND they will reverse/rip-off your product.

Actually what I am surprised about is that they even approached you at all. Products manufactured for the domestic Chinese market generally don't need to give a shit about the legal aspects of the GPL. Until somebody successfully sues a Chinese company in a domestic court and wins damages (vanishingly unlikely), BSD, GPL, LGPL, Apache and other licensed open source things will continue to be incorporated into embedded products with no attribution or licensing agreement.

Yes, they really don't care about any open source license. In fact, they are notorious for GPL violation.

What they were looking for is the Real-time face detector implemented directly in the C code which is available only for the commercial version of the library (https://pixlab.io/downloads).

If I were an unethical Chinese company that really wanted your library, I'd create a US LLC, get some web designers to make a decent looking page that looks real enough, license the C code for some small bespoke project, and then disappear once I had the code/library.

Or just get an agent hired at your company. At lot of companies don't even limit source access to devs. If they got someone in QA or sales with network access they might have enough to grab your code.

> I'd create a US LLC, get some web designers to make a decent looking page that looks real enough, license the C code for some small bespoke project, and then disappear once I had the code/library

This may be an unreasonable risk-reward tradeoff. On the upside, you saved some money. On the downside, you risked (a) an international incident, (b) being cut off from future updates and (c) bringing unnecessary attention to your surveillance project. Much better tradecraft to try buying cleanly, thereby incentivizing everyone on both sides to co-operate, while keeping the shady tactics as a back-up plan.

If you were Chinese intelligence you'd surly reqruit a lot of people in us colleges and make sure they got hired into firms working on this stuff.

But, if you're a nation state, I'm sure just throwing money at the open market will work too. I'm sure that for every company that refuse defence contracts, there are a number that will hapilly build a pink fluffy-looking drone with built in facial recognition, 250 grams of explosives and a proximity fuse. Or, just be willing to sell surveillance tech to authorative governments.