Who are you taking shots for?
In the last 12 months I've done quite a few festivals and have learned that the organisers (and papers) - slightly disappointingly - are not really interested in cool shots of the bands, they want the crowds and atmosphere.
I love taking bands, and from your linked previous festival, so do you!
The reasons are fairly easy to explain.
The band shots could be taken at any festival. The bands provide their own promo shots, so even if the band comes back to the festival next year they are unlikely to use your photos for publicity. Good shots capturing the festival atmosphere are likely to get used in reports of this year's festival and to promote next year. In the festival website gallery, crowd shots always get the highest number of hits on the festival website.
I think it's important to include some band shots; but in my early festivals I did kind of get fixated taking them and wasn't thinking about what was really needed.
If you are taking for the band - that's a whole different ballgame
Here's a band shot - could be taken anywhere
With a press badge on, people will ask for their pictures to be taken, they often turn out to be nice images.
With a press badge on, you won't get glowered at wandering around with a big camera.
Try stuff and see what happens - to get to this high spot I had to squeeze through a lot of people, no problem with a bit of courtesy and a press badge
All the above shots were Status Quo and the Bootleg Beatles at Glastonbury Extravaganza; I was lucky enough to get a press pass to take pictures for the organisers.
My main 2p to add to the earlier suggestions - talk to the venue security boss before things get busy, he will know what restrictions are being enforced. Restrictions will vary venue by venue and artiste by artiste; don't make assumptions.