I’m pretty sure that using high end chemical warfare detection capabilities is very niche(they certainly don’t use them at the entrances to military bases of my acquaintance, at least not routinely); but if someone was going to do it; a company with a variety of unsavory foreign policy entanglements and a business model that involves cultivating ‘engagement’ from a not always well-hinged userbase in most any flavor and at almost any cost seems like a plausible candidate.
That said, given how similar a lot of G-series are to common, legal, pesticides false positives would be quite trivial; by accident or for the lulz.