I use this from time to time while I'm out to avoid and report incidents. It's been helpful so far and helpful when the SYNC system is acting strange in my cars. Plus it's helpful to creep on @sda3 from time to time.
Just came across this article over at Jalopnik:
Waze Thinks You're Cheating If You Drive Too Much
I haven't had any issues since signing up but I don't rack up a crazy amount of miles per day either.