Three Song Rule

Mods please feel free to move this post if it's not in the right section.

What are the implications of not sticking to the 3 song rule, if instructed by a band? The first 3 songs with little atmosphere when a band is warming up is pretty darn tough to get good or varied results eh!!!

Here's the info:

I currently have a (verbal/trust) arrangement with a venue to shoot some of the visiting acts - recently Black Rebel Motorcycle Club, Iron and Wine, coming up will be Gregory Isaacs, Buena Vista Social Club to give you some context. The venue size is c.1500.

I supply them with a selection of web-sized images from each gig, which they put on their web gallery with my watermark. They may also choose one image from a choice of these gigs at some point in the future to enlarge and frame/hang on their premises, or use some pics as marketing to prospective promoters.

As far as the venue is concerned I have full access, except backstage, and am allowed to take pics from the entire gig if I choose - essentially 'carte blanche'.

Some of the recent acts have instructed me via venue staff with the 3 song rule, which is "first 3 songs, no flash" - the 'usual fare' where this rule is concerned. (Iron and Wine was a p.i.t.a. as your man sang the first 3 songs solo with guitar and sole blue light, then full band came on for the 4th and lights opened up.... bitch!!)

I checked with the venue owner the first time who suggested 'carry on until you're challenged'. I can see he wants some half decent pics. The venue staff have never bothered me (been cooperative more than anything & let me get on with it) except I don't return to the front as I know I would be challenged and told to stop (the stage front minders actually issued the instructions and checked with the tour staff, so they would need to be seen to comply).

So...

Where do I stand from the point of view of the band? I have no intention of selling on the pics (at time of writing ;) ) so they will remain between me, my portfolio which may be published online or at an exhibition at some point, and the venue.

Could the band object or raise any legal issues or notices or make any demands? I was not told/made to sign any contracts or releases or other bits of paper.