In the footnote the Chofetz Chaim depicts the severity of the travesty of accepting rechilus with two examples. He felt this was an issue rampant in his day and the problem of accepting rechilus is worse than speaking it since it forwards a situation to continue to down spiral and get worse.
The first example was the case of the non-Jewish landlord who kicked out his Jewish tenant and he blamed a Jew for tattling on the Jewish tenant so if the Jewish tenant believes the non-Jewish landlord that a Jew tattled on him and he now hates this Jew and at some other point he tattles on that Jew and gets him into trouble and now he definitely transgressed rechilus and who knows if the other Jew said anything maybe the non-Jewish landlord made the whole thing up. That’s the danger of accepting rechilus!
The second case is where a non-Jew buys wine from a Jew pays for it and leaves his battles by the Jew’s store for the Jew to fill them up. In the meantime, he shops around for a cheaper price and finds another Jew who is willing to sell him wine for a cheaper price and was not told anything about the first sale. The Non-Jew goes back to the first Jewish and ask for his money and barrels back because he got a better deal someplace else. The Jewish salesman asks whose gave him a better deal and the non-Jew not wanting to get in trouble “innocently ” says your Jewish counterpart down the road told me you have high prices and don’t buy from you; he’ll treat me better at a lower price. The first merchant believes this and is furious at the other Jew. They are at each other’s throats and try to ruin both each other’s businesses all because the first Jew believed what the non-Jew said whereas in actuality the non-Jew found the other Jew and the other Jew didn’t even know about the sale of the first Jew. But even if the rechilus is true there is still no reason to believe or act upon it unless to look more into the matter and protect yourself, but if you ignore what happened and is polite to the other Jew, he might see it’s better to be nice and not to act maliciously and he might even change his evil ways. You can set an example for others and avoid a lot of fights by not accepting rechilus.
Note 5 in halacha 3 and halacha 4 with note 7 says that even if there are rumors that someone for example is the thief that stole from you, you can’t rely on the rumors and must investigate unless witnesses testify and the court finds him guilty or if he is known to be a thief, not just rumors than you can assume he stole it.