There was... stuff.. that happened at one point. To my knowledge, it no longer exists. But BC, Forestry, RC, and a few others would 'check up' on each other, if installed, to ensure they they were 'legitimate' copies. If you screwed with certain parts of the code, or if you copypasted large swathes of code, it would crash you. This was a good while back and, as I've already said, to my knowledge it no longer exists.
Also, CJ and Sengir were (until Spacetoad came back) the primary developers for BC. Both of them are 'known' (and I use the quotes intentionally. Pretend I'm using air quotes) for promoting/using/encouraging 'DRM'. Which is why I mentioned the developers rather than mods and why I was surprised that BC wasn't included. Supposedly, it actually was, just poorly implemented.