Shadowjack was notorious for making threads about stealing being nerfed Hell he may have even started this thread, I haven't checked! lol
I can't remember the specifics of it... but I think it means you have to let that count decay or it might be a solid 2 weeks or a week in real time that they boot you out of the thieves guild.
You need to have the character logged in for 40 hours to get rid of a long term murder count. Say in game "I must consider my sins" and it will tell how many counts you have