I am a server owner for PvP, but on my server, admins and I don't fight or raid. We mostly play legit too, otherwise we would be bored as hell after spawning everything in, but for events I spawn in Tek structures.
If people are hosting the server, they should be able to play how they want! Obviously though ppl will always complain usually the players that cry the most they are hardcore PvPers, are usually the biggest complainer when they get raided, and then they leave server... it will always happen no matter if an admin plays or not
But I agree, if they do play and they have crazy spawned in stuff they should warn the players before they join