In LAN servers, everyone's ID is "LAN" which makes add-ons that save persistent data based on bl_id not work, and also removes any build trust ability
As far as not allowing dedicated servers, I don't see any reason for this. My guess is it was something that for some reason required an admin to be present, and the maker didn't feel like working around that requirement
onPlant and onLoad are exactly what they say they are: onPlant fires when a user plants a brick, onLoad fires when a brick is loaded from a save file