I could say a lot on this, as I've been in the whole premium audio/audiophile thing for a little while (I don't buy the hype, I just want something that sounds good but doesn't break the bank).

What I want to mention is that cd shavers have a purpose, but it's not necessarily good for audio/audio quality. To put it simply, if a disc is unbalanced and wobbles in the reader/player, it's prone to errors. With audio, most of these errors are correctable, and at most generate artifacts in the sound (like ticks or pops), but with faster readers, usually with data storage (like 48x or 52x cd/dvd readers) those errors can cause some significant issues where the disc needs to be re-read. The wobble of the disc due to balance issues can be a significant factor at high speeds.

Shaving a disc, which is really just trimming excess material until the disc is circularly uniform, can reduce errors and increase access speeds.

While all of this is possible, in practice, it doesn't really matter all that much.

I will finish by saying: you won't notice if a CD/DVD/BluRay is in balance, but you will definitely notice if it's significantly out of balance.