Preparing baked potatoes six hours in advance and keeping them in a warming cabinet is possible, but it requires some careful steps to ensure that the potatoes remain safe to eat and maintain their quality. Here's how you can do it:

1. Baking the Potatoes: Bake the potatoes until they are fully cooked and tender. You can add a little oil and salt on the skin to enhance flavor. Ensure they are properly cooked through.
2. Cooling: After baking, allow the potatoes to cool at room temperature for a short while, about 20-30 minutes. This allows excess steam to escape and prevents them from becoming too moist inside.
3. Wrap in Foil: Wrap each potato individually in aluminum foil. This helps retain heat and prevents the potatoes from drying out.
4. Store in a Warming Cabinet: Place the foil-wrapped potatoes in a warming cabinet set to a temperature between 140°F to 160°F (60°C to 71°C). This temperature range keeps the potatoes warm without overcooking them.
5. Check Moisture: Periodically check the potatoes in the warming cabinet to ensure they are not becoming too moist or soggy. If moisture builds up inside the foil, you can unwrap the potatoes for a short time to let excess moisture escape.
6. Serve Fresh Toppings: Prepare your desired toppings and accompaniments separately and serve them fresh when it's time to eat. This includes butter, sour cream, chives, bacon bits, or any other toppings you prefer.

By following these steps, you can serve baked potatoes that are warm, delicious, and safe to eat at your event. However, it's important to monitor the warming cabinet to prevent the potatoes from overcooking or becoming too moist. Be mindful of food safety guidelines to ensure the potatoes remain in the safe temperature.