Aggelos
Ancient Mariner
Because Madness Live is the one who actually pays for everything in Cartagena, while Maiden are the ones to pay at Knebworth.
it doesn't matter who's paying, the principle is the same.
make more than you spend.
you invite good bands, you pay more, but you sell more tickets/merch etc.
obviously this is a 3 day festival, but the supporting bands are so much better. Maiden could easily do something like that.
Why they didn't?
Probably greed.
They thought Maiden alone would sell a lot more tickets.