Advertising a server in other servers will make players go check the other server out and even make players leave the server they used to play until some random player advertised the ip. Making sure that they dont advertise such things in a server for no reason at all just to get some players would not be okay and should be handled.
Advertising is really important because if a server doesnt advertise then no one is gonna know that this awesome server exist and the Owner needs players because without players its not fun also to advertise a server you need to add it to a voting website and pay some youtubers to review the server and I think the staffs should help with that!
I think it is very similar with a minecraft server. If you don’t advertise no one will know you exist and thus no one will play on your server which in turn means you have no revenue and you can shut down your servers. In short, without advertisement no minecraft players and therefore no server.
Advertise your Minecraft Server: http://minebrowse.com/
Minecraft Server Review Blog: https://serverbrowse.com/