The basic idea is that for each populated area frequented by the PCs, that they have a constantly accumulating Party Wealth Notoriety rating, represented by a positive or negative number (almost always positive) that you can use as a modifier on a D20 roll to see whether somebody has noticed that they're suddenly lugging around a fair amount of coin and who in particular is doing the noticing.
NOTE: These modifiers stick around, so if a party loots 3000GP from the Temple of Pointy Things, heads back to Village Town, sells a tapestry, has a wizard identify that weird fish statue and has three members wearing equipment that they other found in the dungeon or bought recently, they have a notoriety rating of +8 for Village Town at this time.
- +1 for every 1000GP of loot taken from dungeon -- not only people noticing the party's loot, also that the loot might be noted as going missing from the original source
- +1 for each unique/notable/powerful item that would likely have somebody potentially scrying for it/capable of detecting it being moved, etc.
- +1 for every extravagant gesture -- e.g. buying the entire bar a round on them
- +1 for each party member or hireling with notable or noticeably better equipment
- +1 for each third-party involved -- i.e. using a non-party wizard to identify a magic item, selling looted goods to a merchant, etc.
- -1 for each week the party is absent from this particular populated area
- -1 for each previously unsuccessful mugging
NOTE: This should go without saying; still, for the sake of clarity, the GM should feel free to pick the most relevant/interesting result rather than automatically taking the result of a roll -- some of the results may not be appropriate for a particular campaign or the locality where the players have been observed.
1-5: mostly unorganized crime group (bandits, thugs, youth gangs)
6-10: organized crime group (Thieves Guild, for example)
11-12: an ambitious minor noble and his underlings
13-14: rival band of adventurers
15-16: local religion or cult who is interested in a particular item/needs money for more gilt/frogs/virgins/etc.
17: a large trading syndicate (if rolled/selected, apply halved notoriety bonus from this area to all other areas said syndicate has their fingers in)
18: unscrupulous wizard with a research interest in certain item/needs money for further research
19: widespread religion interested in particular item/the altar could really use a bleeding bowl of *pure* silver (apply halved notoriety bonus from this area to all other areas this religion/denomination is active)
20: Major player/head of government (apply halved notoriety to all other population centers under the control of the same government)
To continue the example of the earlier party, they decide to head back to the Temple to continue clearing out the lower areas. With their modifier at +8, we roll a 15, getting a 23 in total, so somebody has decided that the reward is worth the risk. Who? A roll of 12 on that table indicates that a local Baron has received reports of a group of wealthy adventurers from his men in town and will have to investigate whether the party has been paying the appropriate taxes/tithes lately, with the upshot that the party is likely to be greeted by a not-insubstantial group of military the next time they leave the Temple. This should then naturally lead to a number of possible choices: Do the party fight? Can the men be bribed? Will there be a trial? A fair trial? Will they be put in chains? etc. etc.