Luke, I reported simultaneous crashes on two machines when my network connection to Slush's pool was lost. I had not configured a pool rollover, so I'm not certain that a pool-switch was involved but it seems likely that one was attempted.
To answer your underlying question: yes, both machines were AMD 7770 GPUs running under OpenCL.
Luke, just to add to this: I have experienced simultaneous crashes on 3 machines when bitminter hiccups. I have FPGAs only, no GPUs. This was on versions prior to 3.0.1. Win7/64.
I have been running 3.0.1 on 3 instances for 17 hours now without issue ... but bitminter hasn't hiccuped yet. When it does, I'll see if my 3.0.1 instances crash.