Ive always found issue with that particular rule. For instance one could successfully argue they entered kobolds ruins and an hour later ran into a party in the bat cave who just so happened to be opening a chest. Of course they entered through the gibberlings so who is right? Also the rule actually encourages stalking which most would consider griefing if they were the victim. I got the point of the rule but its open to wide interpretation from devious sorts.
Not to discount using dm's but keeping it in game allows for much more in game stuff and way less bothersome he said/S(he) said. For instance if you happen upon the person who ran by you earlier now at a chest! let him have it. call him a dirty rotten pilferer who couldnt cut it as a real warrior. those would be fighting words so maybe use *mumbles really quitly* rotten bastard i hope your greed gets you killed. instead of /w "rotten bastard i hope your greed gets you killed". it sucks people are jerks but its one of the truly real aspects of Pw's, jus like life
Also i totally agree with your assessment of how people react to being advised as to their actions. Which means sending tells is a no go zone imo. keep it in character and know death is not a punishment but a release.