The contestants must have some idea when they are going to be chosen,as when they go to the crazy chair their nearest and dearest are always sat directly behind and always 2 rows back.
The contestants have to wait 20-odd games before they are chosen,so do channel 4 pay for for their family members to stay in hotels from day 1 until the day they are chosen if it's all random?
The contestants have an idea of when they might be chosen ...there are 3 episodes filmed each day. The programmes are edited & I assume friends/family of the chosen contestant are moved to those seats between shots but I doubt that their accommodation is paid for.
when you go into the studio you sit where you like but when the contestant is chosen the filming stops and whoever is sat in the seat where the family member has to sit has to get up and swap with them, i know cos i was sat in the seat!