This is quite hard to answer, because of the nature of the problem. There are no clear boundaries.
You should build a robot that is stable and robust enough to sustain a 8 minute game. If the robot needs repair during a run it is not a good rescue robot, right?
But I understand that there is a difference between tighten a single bolt and remounting wheels that has fallen off.
To be fair we have said that the teams are not allowed to repair a robot during a lack of progress, see 3.6.3 "Team members are prohibited from [...] repairing the robot during a restart". I think the referee should have referred to this rule.
In an ideal world (maybe in the future) I would prefer to have the judges to start and restart the robots. So the teams can't modify, repair or pass any information to their robot. In Trinity College Fire Fighting Robot Contest it is like this.
Hops this answers your question?
// Fredrik Löfgren, TC and OC member 2016 / 2017