All that means is people are laying bets. Why is there an assumption that the bookies have an inside scoop? Or are ITK? They know as much as us and odds tumble when fools wish to part with their money. If the bookies knew Gallardo was to be our manager for a fact then you wouldn't even get odds on him.
The logic is, odds shortening, somebody been told something, so they have lumped on, then told others, who have lumped on, the bookies think, hey up and shorten the odds.
Most of the time it doesnt take more than a few bets.
Unless hes 1/250 pretty soon then I wouldnt pay much attention.