That's gotta be the cover-up so they can quickly so, "oh! It was an anonymous tip. No one to blame or possibly endanger for you crazed vigilantes--sorry, thanks!"
I feel like when you start conspiracy theorizing you're obligated to follow it to its logical conclusion. If I thought it were a cover-up to protect the store from crazed vigilantes, the last thing I'd do is try and put the store back in danger!
Giving the reward to a minimum wage worker seems like something he would do if he wanted to give himself up to the police, like why just go to the cops, the reward would be wasted. Although his politics seem incongruent so maybe not.