Well, i have thought about this as well before i got all my tracks registered at AdRev.
I can imagine a lot of customers would like a no content ID track to begin with… not as a priority, but simply because it can be a bit of a hassle to prove that you have bought the track and have to take time to do so.
I have gotten a few angry people as well who cannot believe that they have gotten a claim and have to prove that the track they use in their video is bought by them.
I always calmly explain them how it works and why I do register my tracks.
That is my second point… i have heard so many horror stories of authors having their music stolen, and then get a claim theirselves on their own content! In order to avoid this at all costs i simply have no other choice then to register my music.
Also, i have gotten quite a few claims on people who stole my tracks and used it for their videos… even one with 6 million views now, so that is a nice amount of content ID cash coming my way soon.
Eventually that person bought the track as well, without content ID i would have missed this.
Conclusion for me is that people steal, or worse… steal and claim it as their own making you look like the thief.
People who work in the business as video creators, editors, moviemakers, etc… understand this and will have no big problems with content ID.
Some will find it a hassle and avoid it, but you have to balance this out for yourself… losing a few customers who dislike content ID, or risking getting stolen from.