In real life, it's unsavory, dangerous, or disgusting actions done in urban rental property - be intentional or unintentional - to deter new tenants and force the landlord from increasing the rent (as no one would normally pay high rent for an unsafe or unkept property, and the existing tenants stay because of the lower price).
Online, it's a community's acts of exaggerated unpopular behavior as a way to gatekeep by attempting piss off and deter unwanted members and behaviors on purpose. Said behavior may not necessarily be how the community actually behaves.
Guy 1: Landlord's about to increase the rent
Guy 2: *plays porn on max volume* *discharges a pistol in the air* *pisses on the floor outside*
Guy 2: There, I'm keeping the rent low
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User: Hey Admin, the server's starting to get more Anti Shippers
Admin: Get me pics of incest ships, I'll plaster it in the announcements channel to keep the rent low
Negligent discharge of firearms close or inside urban rental property, be intentional or not intentional.
Playing loud music and watching pornography on high volume.
Better exicuted if your neighbors are as cool as you.
Guy 1: "Hey neighbor, did you hear a gun shot last night?"
Guy 2: " That was me keeping the rent low. Friend in apartments up the block said they raised his rent"