while it isnt wide spread, it also isnt unheard of. blitz can hard lock an xbox 360 at random times durring a song. after months of being frustrated, i finnally think i got it nailed down, and as i can reproduce the results on a whim i am sure of it.
basically, if you skip through the song results screen rather fast, it de-syncs with rock central resulting in the game hardlocking the system most likely in the next 2 songs you play. if you give each screen time to do its update animations(adding points, coins and cred) it should stay in sync and the game can be playable till you want to quit.
bear in mind, no client side patch has been applied, and i can still force the system to hardlock within 2 to 3 songs by skipping the results screens.
this is nothing like the 1000 song issue that everyone feels the woes of, i only have 930ish songs and have played less than 150 of them(mainly because the locking problem i was having)