That normally involves 5 kids - but seems the most likely explanation. Although, last time the treat was at Alton Towers, they only filmed Spinball Whizzer (oops, sorry - Sonic Spinball :))
No not if a trip to Towers was the final prize and they lost so one person did the last trial but there bestest bestest buddy decided it wasnt fair and went to shovel horse poop with them and they fail leaving only three kids to go to AT ...
... What? ... Thats what happens ... I have seen it ...
I have seen it as well but the only way they could have 3 left is if they failed one of the other challenges. The contestants aren't allowed to help their friend out unless it's a 5 person task. They can't choose to play a task just to keep their mate company.
And I forgot that they could lose people from treats, I haven't seen it on a while. So yeah, it probably is best of friends.