From what I've heard, HC is going into almost all the LPs and double checking whatever they want.
That said, I was looking at the testing processes yesterday and honestly, there's so many ways to do it, parts of the plant they could test, times they could test it at, etc. Who says they aren't dusting a small amount in THC and sending it for testing.. it's a really hard thing to document accurately from what I've read.
That said, I'm still trying to figure out what HC considers a valid test in this area. They don't specifically name a process, they just say it has to be tested. To the best of my knowledge..