Please read the Roblox API on DataModel:SetPlaceId. This can only be used in the command bar and plugins. It’s intended use is to give a local studio file on your computer a PlaceId to properly work with DataStores.
SetPlaceId is not a very common command, and is limited to the command bar only (not even plugins).
There is an almost 0% chance you can prevent map leakers; exploiters can do anything they want with the client, and replicated models are on of those things on the client.