You will be banned for 72 hours if any griefers decide to report you for revealing their location. I recently encountered a group of people who were being very toxic to me and another solo queue player. We didn't fire back with any insults or anything, but there was one round where the griefers were doing circles and shooting in the middle of the map and I told the enemy team where there were and to report them.
Jokes on me though, they've all reported me for disrupting the team and I've gotten the ban instead. Lesson learned.
E: some are under the impression that I'm saying you can get banned for saying just "afk." This may be the case, however I think saying a specific spot like "afk at B" is where the griefers will get you.