I'm not convinced it is only an SIII issue. My phone is a Sony Xperia T and I have recently getting the SD card unexpectedly removed messages, so far hasn't killed it.
Sony may use the same material when assembling the SD card mount point, or might be an issue with the Android itself. I googled around and found not only SIII topics
I also have Samsung SDHC 10 32 GB, my buddy has the same having no problem so far with the same phone (sony).
I noticed that I get this error mostly when I'm in cold places, for example skiing or jogging outside, so might be connectivity issue, however my fried dosn't have.