I feel bad for the United fans who have made travel plans.
As far as advantage is concerned, home fans are an advantage, but then so is being in your home ground, while the other side has had to travel etc..
I suppose with all this, it's about people in power making safety calls & realistically they're probably going to be over cautious (As they were with the volcanic ash cloud thing a few years back). Public safety is involved & decisions now could benefit the longer term outcome. Though it's saddening watching our dim-witted chancers in Government at the moment, absolutely zero leadership. Zero. Where is gung-ho Boris and his appeal to the man in the street when the nation needs it?
(got my fingers crossed for my American trip next week ...)