It might come to pass that the characters, or agents working against the characters, might want to know who has been asking about them, or an interest of theirs, around town. Perhaps the players want to know who else has been researching that diamond job. Maybe the local mob wants to know if any adventurers have been sniffing around their turf. In these cases, some Counter-Intelligence is called for.
In the same manner as a normal Gather Information check, a character may indulge in some counter-intelligence. The DC of this check is equal to the result of the instigating party's Gather Information check. Success means that the counter-intelligence-gatherer learns the identities of whoever has been asking after either the gatherer himself, the organization he represents, or a single job or event around town.
A character or group who is especially concerned with taking pains to hide his tracks may take a voluntary penalty on his Gather Information check. This penalty may be any number, but must be at least -5. The DC of any counter-intelligence checks against that character's inquiries are instead increased by the same amount as the penalty.
Example: Argent the Bard is asking about the kidnapped princess, but doesn't want the kidnappers to catch wind of his inquiries. He takes a voluntary -10 penalty on his Gather Information check, to represent asking more vague questions of less reliable people. His die roll is 32; his final result is only 22, but the DC for the kidnappers (or anyone else) to learn he was asking around about the kidnapping is 42.
Counter-Intelligence rules and concepts first developed by Jason Alexander, at http://thealexandrian.net/wordpress/7496/roleplaying-games/skill-use-counter-intelligence. Presented here essentially unchanged.