I can think of two straight (non-DOR/NPQ) attrites from the time I was in OCS, this is for the whole time I was there. One was mostly an attitude case, as I hear (he got the boot just about the time I arrived, so it was all secondhand), and the other just didn't belong in a military environment; I sort of feel bad for the second guy, I talked with him after OCS, and he wasn't a dirtbag or anything, just didn't belong. In contrast to those cases were at least a dozen people who rolled multiple times for RLP, that sort of thing. As others have stated, if you don't quit and aren't a complete imbecile, it's almost impossible to attrite. In regards to the original poster, there just about has to be some extenuating circumstances. Family concerns, undetected medical issues, something that would keep you from being able to perform. I do not know of any attrites who successfully returned, nor have I heard of any stories. I'm not saying it has never happened, but it's a huge black mark, which is why it is so often advised to put in a real effort and don't quit. I did hear of one story about a guy who had a brother with a sudden life-threatening illness. As I understand it, he had to DOR to be able to be with his brother and was allowed back in because of that circumstance, but did have to do the whole program again. Your second, third, forth, and sometimes more chances are given you while you're in OCS, after you leave, good luck.
There was a guy very recently who got attrited from OCS because he had been sneaking off base and going to Wal-Mart to buy candy at night.
Where do these people come from? Getting caught with gedunk in OCS is not a good thing, but usually the worst thing anyone gets is some extra harassment and the occasional roll (not recommending it to anyone, just saying). Just leaving the OCS grounds without permission probably constitutes a UA. Leaving base... Also, I remember having little trouble getting gedunk, entirely legally. Not sure what it's like up in Newport, but in P'cola the vending machines in the OOD rooms got pounded regularly (some other classes were expressly forbidden; in retrospect I don't mind so much that our gunny tended to beat us hard given that he didn't care about that stuff). One advantage of being a smaller class is that they didn't run out as much. I remember as a candi-o with bigger classes coming through, those machines would be stripped of all but a few things. I don't think I've had pop-tarts since OCS, but that being the first thing I would hit up. I think OCS is the only place where I counted calories looking for the most sugar. Anyway, I'm rambling on now. My excuse is that I'm awash with memories, as this is the two-year anniversary of my starting OCS. Good times, good times... (yeah right)