I think, if it's possible, the band should put on two shows at each venue. One, no tech show at reduced prices. Instant ejection for any visible tech.

Second show, vastly inflated prices but the audience would be allowed to use all the tech they want.

In fact, the band could cut out the middle man and save a lot of fuss by, rather than performing the show personally, they could just run a film of the first concert on the screens at the second concert. Result. Everyone is happy .