Aside from that, I think that HMX would be very careful about not ruining the rock band name. Tracks are to be submitted and play tested before being released. So the thoughts of having terrible charts may be unfounded.
I think that the majority of bands that will be on it first are the unsigned bands that have enough money that go on small tours (local venue tours). There are a lot of bands out there like this. They go the route of the DIY cd (no label involved) and see more money from the sales of their CDs, and now they can expand their exposure by adding songs to rock band. Record labels don't like uncharted waters, and major acts may not be able to jump in if the label says they can't (unless the finance it themselves or something to that effect).