Almost 40,000 turned up when Wales played at Hampden in March, only for Scotland to deliver a woeful display, one of the worst in recent years, and lose the World Cup qualifier 2-1. Instead of furious derision from the stands, though, there was a sense of numb acceptance which alarmed manager Gordon Strachan and McGhee in the technical area. Their fear was that Scotland had disappointed the supporters so many times of late that fans had lost their capacity for raw anger.
"What brought it home to me was the kind of shrug of the shoulders after the Wales game," said McGhee. "There wasn't a tumultuous defiance about being beaten by Wales. There was a shrug and a feeling of 'that's what happens to us'. We have to change that. We've started that process and now we have to continue it. We lost to a great side in Belgium [in the only other home qualifier so far this year] but it was at home and it was another defeat."
McGhee admitted the worry is that supporters have become utterly accepting of mediocrity and will no longer pressurise the players to improve. "I think it comes from the team," he said. "If the team produce mediocre performances and results then that becomes the norm.
"Of course what we're trying and hoping to do is change that mentality. There has to be a certain pressure on the players, there has to be a certain level of expectation to put pressure on the players to force a performance. I don't think that's a bad thing.
"I don't think all the pressure being off is the best way to get a performance. They need a little bit of pressure and expectation [from the fans]. They need to think 'right, we've done well in these four games, we've beaten Croatia away, now we can beat them at home'. That sort of thinking galvanises you."
Scotland finish their World Cup Group A campaign at home to Croatia on Tuesday. By then Croatia may have been confirmed in a play-off place if they fail to defeat leaders Belgium in Zagreb tonight. Belgium are five points ahead and both countries have two games left.
Scotland are currently fourth, in line with their seeding before the campaign began.
Jordan Rhodes is the only player to have withdrawn from the squad, although Norwich City midfielder Robert Snodgrass has still to join the group because his wife is due to give birth. He is expected to travel north once the baby has arrived.