I’m a lot less bothered about rules lawyers than Seth Skorkowsky. In fact it can be useful to have one in the group (who can remember the contents of all those GURPS books in the thick of battle?) and as I’m constitutionally opposed to autocracy I invite the players to cite the rules to challenge my own whims.
I wonder if Seth may have cherry-picked to prove his point, as the example of the player trying to claim a bonus for every use of their spouse’s name does indeed sound irritating – but there is another possible interpretation. Some players take note of the sort of roleplaying flourish that pleases their GM and then exploit that to earn special concessions. So if the original player shouting out his wife’s name was true to character, all well and good; but it could be that the rules-lawyering player was actually making a sarcastic comment on sucking up to the GM’s tastes.
On police and mysteries: in a modern and familiar setting, I find it hard to swallow amateurs in a murder mystery. The police might not solve a murder, but if they aren’t at least getting very cross with anyone else larking about with crime scenes and witnesses, I don’t find that plausible.
On the flip side, there’s lots of scope for mysteries focused on other crimes. Roger’s His Body, His Flesh, and His Bones worked well for me because it’s a missing persons case and someone the police aren’t that interested in. The genteel detective in the Christie mould feels like a better fit for things that are scandalous, rather than serious crimes: the evidence is rarely good enough for any kind of conviction, but convincing everyone else is sufficient. It works for matters of honour, professional reputations, journalists ruining a political career by uncovering dirt, etc.
One problem in a series/campaign is that working round the police is basically one-note, like not understanding the language. There’s only so much you can do with it, but it has to happen every time.
“This death looks like an obvious accident, and only you understand how it could have been murder” has some possibilities.
Another one is where everyone involved wants to steer clear of the police, so the death goes unreported. That gives options like being part of a stigmatised community, having shaky immigration status, organised crime, or living under a repressive government.