my usual approach is to bury it down a ways, and burn the toilet paper. not much happens in the desert. you know the stories... patton's tank tracks from training still visible in the mojave from WWII. i avoid washes and areas of flash flooding, but if you put it 8" down in the desert, it'll probably stay for a long time. i've heard about the smear technique more for high sierra, above-timberline, situations.
also, kevin, if you are starting to think about socal on the pct... lots of folks refer to the much of southern california as "desert" but actually very little of it is. i'd call the corner of the mojave desert through antelope valley desert, but not much else. the rest is just good old fashioned chaparral, coastal sage, and lots else. just hot and dry. and if you're in the desert, i'd sure bring paper. nothing like a bit of creosote bush, burro weed, and cholla to make you miss some fluffy charmin.