Mods and cheat engine

[Lunatory]

The ledge sit is quite innocent despite the fact that it does go against ToS and may be doing more.
I won't presume to know how it all works, but I'm making an assumption that these type of mods like the ledge sit that affect what other players can see is a result of it sending information to the server itself meaning this is not a mod that's affecting the user's own client but actually sending faulty information to a server that is not your IP/personal hardware. It's one thing to modify your own client, it's another to send modified information to a server.

While I can not speak for the Cheat Engine method, the same can be replicated by hex editing the hotbar file in your My Games folder. The /sit and /doze emotes function as shortcuts and the game (client) will decide which actual emote to send to the server. If the client detects you sitting on a chair, you'll play the chairsit emote. If not, you get the groundsit emote.

You hex edit a hotbar slot to make you play the chairsit emote directly rather than the normal /sit shortcut. The server will accept this input since /chairsit is a legitimate emote and the server does not care to double check if you are in fact on a chair.
If I wanted to I could back up my hotbar file to SE's servers using the character select screen and load it up on my Playstation and proceed to chairsit anywhere on the Playstation version of the game. No network hacking required in the slightest. Just manually firing an emote that is normally only fired through /sit or /doze. I imagine the Cheat Engine version does just this as well?