The stance in testing is that if you can't hit it with a stock RB kit then it isn't allowed.
I've called some authors out on it, because there was bass notes charted that I didn't think could be hit on a stock kit with just one pedal, but they swear up and down that they (the authors) can hit them.
I'm not an elite expert player so I couldn't hit them anyway, but I will be the first to admit that it seems like RBN songs are charted on the harder end of the spectrum for each difficulty.
I agree that it seems some of the songs are charted more difficultly than necessary. Some of them just give off a Guitar Hero/Frets on Fire vibe as opposed to feeling like Rock Band charts. It's not a big deal or anything, and I don't think for the most part that it hurts the fun much. Just something I have noticed.
It's certainly not all of the songs though, many of them are a blast to play to play and feel great. But there are definitely some with very awkward sections that seem overly hard just for the sake of being hard. There seems to be a higher percentage of awkward chord changes as opposed to switching to a combination that doesn't require moving your hand all over the fretboard, for example. That's a note my brother has made anyways, he's the guitarist. <_<
Just to be clear, I'm only discussing about the logic behind it, it's not that it matters a lot or that I'm somehow angry about it, since I wouldn't even care for the double bass charting. It just seems that since RBN is giving new opportunities to chart songs, it would be a shame to see songs charted in a more awkward way to make them more difficult while still respecting the Harmonix double bass pedal standards when we could simply see double bass charts for RBN songs that the authors choose to chart that way.