I know this isn't what happened, but what if one day I'm waiting for the bus and I over hear a guy talking on their phone about an imminent acquisition? 1. Would that still fall under insider trading even if the information was accidentally heard, and even if I wasn't 100% sure of its accuracy? 2. If I had no clear connection to the company how would it be proven that I was trading on insider information? Surely it's…
In this case though you’d probably have a good defense to those charges. It’s possible they’d interview you and look into it more and see this plainly before bringing those charges. If they did though, even with a good defense, it’s going to be disruptive to your life and finances.
The fact they were speaking about it in public and you have no connection to them makes it plausible for you to think that what you heard was public information. The onus is on them to protect sensitive information like this so they could actually face some problems. It’s very much going to vary by all the people involved with the investigation and what they want to do with it.