It is worth noting that BS7909 is very much the new kid on the block in standards terms - being truly fleshed out for the first time in the last ten years or so  (there is a 1998 version but it is very different), (new is relative, compare the original wiring regs from 1880 or so, and how long that has taken to mature, and it is still being optimised) many of the old hands working in more senior roles on-set now will pre-date BS7909. Training courses based on the standard are even an even newer phenomenon, however, it makes good sense to include this as a starting point for someone coming at it from outside, though I suspect you may find that a great many,  (if not most) folk working in the events electrical area have not been on a BS7909 course of any kind.

It is worth noting that BS7909 is very much the new kid on the block in standards terms - being truly fleshed out for the first time in the last ten years or so  (there is a 1998 version but it is very different), (new is relative, compare the original wiring regs from 1880 or so, and how long that has taken to mature, and it is still being optimised) many of the old hands working in more senior roles on-set now will pre-date BS7909. Training courses based on the standard are even an even newer phenomenon, however, it makes good sense to include this as a starting point for someone coming at it from outside, though I suspect you may find that a great many,  (if not most) folk working in the events electrical area have not been on a BS7909 course of any kind.