Will I be banned if I use a tweaked Coalesced.bin file in multiplayer?

This story shows a user who got banned for joining a multiplayer game in which the host was using modified game files. The player got illegitimate credits and spent them, resulting in the ban.

To quote a user on the BioWare forums:

Why does EA bother to ban people for using tweaks ? Simple. If those tweaks provide access to credits (that are being used to buy packs) or even worse gear, they will ban them outright, since their purpose is to make people want to purchase the packs, for real money/Bioware points.

I would say, better safe than sorry. Keep a backup of the original bin file and swap it for multiplayer. One of the simplest ways of detecting modified game files is for the executable to do a checksum of all support files. The checksum comparison routine is simply a pass/fail if the file has been tampered with, so there is no sorting out the innocent from the guilty.

If you are modding to steal EA's revenue, I am sure you will be dealt with at some point. Getting credits is a prime example because EA sells BioWare points to purchase the same items as credit points are used for. You have a high risk of getting reported when you publicly strut your stuff in public rooms. Other REAL players will not appreciate being robbed of credit points. Finishing gold match after gold match solo could easily get you noticed and booted. So, to make a long story short, if you paint yourself to be a target, you deserve to be banned. I have been running mods over a month and knock on wood I have not been banned. I also buy BioWare points to get packs and almost never finish matches. If you must Mod then my advice is keep it real. There is no guarantee you will not be banned.