This problem I think I already detected in January 2008 but never really thought of it to be such a big problem. After reading this, it confirms that PS3 discs are prone to wear and tear.

I have bought many used games before but 1 game really caught my attention because the disc had small crack on the center ring exactly like all the photos shown in this thread. And the weird thing is, this happened to an R3 disc

That game was a used Resistance (R3). I asked the seller (a forummer here) whether he knew anything about the crack but he knew nothing of it and said the disc was perfectly fine when he sold it to me. So I just assumed it was damaged during poslaju delivery. The disc plays fine though, and that's what was really important.

I hope this crack anomaly would be crack down as soon as possible because not many of us can afford brand new R1 games.

That's all from me, thanks for reading

wrong! you must blow on the disc first to cool it down
then only put back inside the case