Ultimately, though, any sort of modification of the game client is a violation of Nexon's terms of service, so you're taking the life of your Milletian into your own hands when you mod. That includes both data folder/package modifications (i.e. Unofficial Tiara), or patcher mods (Abyss).
Is it likely you'll get banned for it? No. Possible? Yes. Either Nexon has to catch you (and they do lurk in the shadows of Dunbarton's shady alleyways!), or someone else reports you.
The infinite party timer is a clear giveaway that you're using Abyss. It's something that cannot be done with a clean game client, and is easily visible by anyone else. If you tell someone what their Combat Power is in public chat, that's also an obvious giveaway you're modding.
Most of the things that the mods on this site do will be visible only to you, with a few exceptions (one example would be the summoning a mini hot-air balloon Action, since that is normally hidden). Unless you're specifically trying to show off a specific modification, avoid sharing screenshots or videos anywhere, especially on the Nexon forums. While it should seem obvious not to post pics with mods on Nexon's forums (you may as well tape a "ban me" sign to you), people still do. Posting anywhere else is a bad idea, too, since someone could still submit that as evidence to ban you.
So, unless it's privately shared with friends, it's generally a good idea to hide your name in modded screenshots (maybe even blur out your character if you have a distinctive appearance?).
I'm not saying to not use mods. I'm saying to be smart about what you do.
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