In "What are the conditions for re-entry of an object in a (highly) elliptical orbit?" Eerie asks about orbital mechanics of orbital decay of decommissioned satellite: starting with extremely elliptical orbit (apogee 7767 km, perigee at 99 km) the satellite's orbit gradually decays until it's nearly circular, when the satellite finally spirals down burning in the atmosphere.
But a fraction of m/s burn at the apogee would be able to drop the perigee into ~30km range, and then the satellite would rapidly burn up, traveling through the atmosphere at way more than 8km/s instead of risking debris surviving the final reentry and causing damage on the ground.
There's no point saving fuel, because the satellite is going to burn up anyway. The maneuver is really minuscule comparing to what is needed to get the satellite to start aerobraking at all. And the higher reentry speed into the thick atmosphere the less chance any debris will reach the ground. Never mind after so many aerobraking passes the landing point becomes completely unpredictable.
So why is the slowly decaying orbit through edges of Karman line used, instead of one that would make sure the satellite turns into a cloud of hot plasma over Pacific? Any rationale for keeping the perigee so high?