It was cheaper for me to go on camp which as a teenager i preferred to going away with the family - holidays that were UK Based anyway and at 14/15 a camp was more interesting, i got the rest of the summer with the family at home.
If you prefer a family holiday, then don’t take a place on camp it’s as simple as that.
But if you are on a family holiday you wouldn’t go on camp anyway.
I would say that a family holiday is far preferable to a cadet camp in the modern era as the camp programmes have become little more than a series of trips out and station based activities run by staff. Mainly because the RAF has shrunk so much that it cannot provide what it once did. Shooting only if qualified staff can go and weapons/ammo/ range are available; section visits, what sections; work experience a big thing in my day, doesn’t happen; flying can be a day out if there is an AEF nearby that is operational.