1800 rpm is not a mild power setting so depending on where you park, thrashing the engine just before shutting it down may get an less than amused response from the other owners who just got their planes sand blasted or rock pelted. Let alone you try that on a busy apron. Makes total sense until reality kicks in.
As with LB above never had issues with fouled plugs with healthy engines even without significant leaning on the ground. When a particular aircraft started to foul then we tried plug changes and leaning, have to also consider oil fouling as the engine condition deteriorates. If its fouling seriously in short periods theres other things at play.