I also didn't understand, because the article doesn't actually mention Google's "spying" or explain it at all. It does link to the NLRB complaint, though. It's

I also didn't understand, because the article doesn't actually mention Google's "spying" or explain it at all. It does link to the NLRB complaint, though. It's a real slog to read through but I think the actual salient points are: * Management "viewed an employee slide production in support of the union drive" (§7), no details but I'd assume that they somehow accessed it without an invitation? * The firing was nominally because the employee looked at another employee's calendar, but the claim is that this rule is selectively enforced (§11b) So the only "spying" I can figure out is if, say, one of the claimants made a Google Slides presentation about the union, then one of their bosses went poking around in the employee's Drive (?) and reading their presentations without explicit permission. If the boss abused privileged access to read what was supposed to be a "private" document, I could see how that's illegal "spying". (Although, hey, maybe don't use your employer's software to make your union presentation?)