This is a general counsel’s worst nightmare. A few forgotten Post-it notes, apparently scribbled on by Google employees, are at the heart of a recently-filed intellectual property lawsuit against the web search giant.

According to a complaint filed in US District Court which lists both Google and YouTube as defendants, Google in 2010 had considered buying Vedanti Systems Limited (VSL) or licensing the company’s video optimization technology. VSL and Google signed a non-disclosure agreement in April 2010, the complaint says, after which VSL shared details about its technology. Negotiations continued for a few more months and then stalled in December 2010. Google then returned materials VSL had sent the web giant.

Here’s what the court case says happened:

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The complaint also alleges that Google began incorporating VSL’s technology into its products after discussions between the two companies fizzled out. A Google spokesperson declined to comment on the case.

We haven’t actually seen the Post-it notes, and don’t know if they really say what the complaint says they say. (We did ask VSL to share them, but it declined.) In fact, we’re not even sure if technically speaking they are 3M’s branded Post-it notes, or just generic yellow sticky notes. (Nor have we any idea why that would matter.)

But what we do know is that this case offers a glimpse of minefields that corporate counsels must tiptoe through, when even seemingly minor oversights—a Post-it note here, a careless email there—can become fodder for enormously costly lawsuits.